Journal of Manufacturing and Materials Processing

51 pages, 14826 KB

Open AccessReview

Challenges and Opportunities in Friction-Based Additive Manufacturing of Heat-Treatable Aluminum Alloys

by Adeel Hassan, Mokhtar Che Ismail, Srinivasa Rao Pedapati, Roshan Vijay Marode, Khurram Altaf and Santoshi Pedapati

J. Manuf. Mater. Process. 2026, 10(6), 214; https://doi.org/10.3390/jmmp10060214 - 21 Jun 2026

Cited by 2 | Viewed by 760

Abstract

Heat-treatable aluminum alloys are widely used in aerospace and automotive industries for high-performance structural applications. However, their processing through conventional fusion-based additive manufacturing is limited by solidification-related defects, such as hot cracking, porosity, and elemental segregation. To overcome these limitations, friction-based additive manufacturing [...] Read more.

Heat-treatable aluminum alloys are widely used in aerospace and automotive industries for high-performance structural applications. However, their processing through conventional fusion-based additive manufacturing is limited by solidification-related defects, such as hot cracking, porosity, and elemental segregation. To overcome these limitations, friction-based additive manufacturing (FBAM) has emerged as a promising solid-state alternative. FBAM primarily includes friction stir additive manufacturing (FSAM), additive friction stir deposition (AFSD), friction screw extrusion additive manufacturing (FSEAM), and friction rolling additive manufacturing (FRAM), which differ in feedstock form and process configuration. In these processes, feed material is consolidated through frictional heat generated below the melting temperature, enabling the formation of refined equiaxed microstructures while minimizing solidification defects. Despite these advantages, significant challenges persist in processing heat-treatable aluminum alloys, particularly the 2xxx, 6xxx, and 7xxx series. These include non-uniform microstructure and mechanical properties along the build direction; precipitation instability; process-induced defects, such as tunnel formation; and mechanical properties that are often inferior to those of the corresponding base materials (BMs). Reported FBAM builds generally exhibit equiaxed ultrafine grains below 1 μm; however, the strength and microhardness of heat-treated alloy builds commonly remain around 70–75% of the corresponding BM. Following post-heat treatment, microhardness can be nearly fully recovered, whereas UTS typically reaches about 80–85% of BMs, often with an associated ductility reduction of nearly 50%. This review critically analyzes research reported over the past decade on FBAM processing of heat-treatable aluminum alloys, covering FSAM, AFSD, FSEAM, and FRAM. The key challenges related to microstructural evolution and mechanical performance are systematically discussed for each alloy series. Furthermore, mitigation strategies proposed in the literature, including process parameter optimization, in-process cooling, post-heat treatment, and nanoparticle reinforcement (e.g., SiC, TiC, Ni and ZrO₂), are evaluated. Finally, existing research gaps are identified, and future directions are proposed to support the development of robust, scalable, and high-performance FBAM processes for heat-treatable aluminum alloys. Full article

(This article belongs to the Special Issue Advanced Additive Manufacturing of Functional and Structural Alloys)

► Show Figures

Figure 1

19 pages, 11966 KB

Open AccessArticle

Efficient Prediction of Cutting Force and Stability in Five-Axis Machining of Complex Surfaces Based on Dimensional Compression

by Jingyang Feng, Jianning Zhu, Minglong Guo, Xiuru Li and Xueqin Wang

J. Manuf. Mater. Process. 2026, 10(6), 213; https://doi.org/10.3390/jmmp10060213 - 16 Jun 2026

Viewed by 512

Abstract

With the rapid development of high-end equipment manufacturing, the number and size of complex surfaces continue to increase. Five-axis machining has become the dominant machining method. Effective prediction of cutting force and stability is of great significance for improving machining efficiency and quality. [...] Read more.

With the rapid development of high-end equipment manufacturing, the number and size of complex surfaces continue to increase. Five-axis machining has become the dominant machining method. Effective prediction of cutting force and stability is of great significance for improving machining efficiency and quality. However, due to the complex and time-varying cutting geometry in five-axis machining of complex surfaces, low prediction efficiency has become a key issue restricting the research and engineering application of cutting force and stability. To address this issue, this study introduces the concept of dimensional compression and establishes an efficient prediction model for cutting force and stability. Each tool position along the tool path is discretized into inclined plane milling based on finite difference, thereby simplifying the research object. The tool twist angle and feed deflection angle are defined to describe the spatial relationship in five-axis machining. Using these two angles as new basis variables, a compressed space is constructed, and a mapping relationship between tool position and spatial point sets is established, further reducing the dimensionality of the research object. The cutting edge contact interval is determined using the spatial constraint method. Based on the full discretization method, the cutting force and stability of inclined plane milling are predicted, and the results are uniformly stored in the compressed space to form a sample point library. Consequently, the prediction process of complex surface five-axis machining is transformed into a process of sample point retrieval, significantly improving computational efficiency. Cutting force and vibration experiments in five-axis machining of complex surfaces are conducted. The results show that the predicted results are in good agreement with the experimental measurements, validating the accuracy of the proposed model and demonstrating its capability to guide practical machining. Full article

► Show Figures

Figure 1

19 pages, 637 KB

Open AccessArticle

Determinants of AI-Enabled Quality Control Adoption Intention in Manufacturing SMEs: An Integrated TOE–TAM Analysis Using PLS-SEM, IPMA, and fsQCA

by Haldun Turan

J. Manuf. Mater. Process. 2026, 10(6), 212; https://doi.org/10.3390/jmmp10060212 - 16 Jun 2026

Viewed by 797

Abstract

AI-enabled quality control (AI-QC) tools are increasingly available to manufacturing SMEs in emerging economies, yet the firm-level conditions associated with their adoption remain underexamined. Building on the Technology–Organization–Environment (TOE) framework of Tornatzky and Fleischer, integrated with the perceived usefulness and perceived ease-of-use constructs [...] Read more.

AI-enabled quality control (AI-QC) tools are increasingly available to manufacturing SMEs in emerging economies, yet the firm-level conditions associated with their adoption remain underexamined. Building on the Technology–Organization–Environment (TOE) framework of Tornatzky and Fleischer, integrated with the perceived usefulness and perceived ease-of-use constructs of the Technology Acceptance Model (TAM), this study examines the determinants of AI-QC adoption intention, and its association with operational performance improvement, in 284 manufacturing SMEs from Turkey, Malaysia, and Egypt. The focal dependent construct is adoption intention rather than realized adoption. The AI-QC technologies considered are machine learning defect detection, computer vision inspection, predictive maintenance, and digital twin integration. Three complementary analytical procedures are applied to the same data: partial least squares structural equation modeling (PLS-SEM) to estimate the strength of the modeled associations, importance–performance map analysis (IPMA) to identify high-importance but low-performance predictors, and fuzzy-set qualitative comparative analysis (fsQCA) to identify combinations of conditions jointly sufficient for high adoption intention. The PLS-SEM estimates indicate positive associations for the technological, organizational, and environmental predictors, with top management support, perceived usefulness, and organizational readiness showing the largest coefficients and data security concern showing a negative association; effect magnitudes varied considerably, and several were small. The IPMA results indicate that the two most important predictors exhibit comparatively low performance scores in the sample. The fsQCA results identify three configurations associated with high adoption intention. Because the design is cross-sectional and based on self-reported, single-respondent data, the findings are interpreted as associations rather than causal effects. The paper concludes with guidance for SME managers, AI technology vendors, and industrial policymakers. Full article

► Show Figures

Figure 1

14 pages, 14853 KB

Open AccessArticle

Research on On-Line Precision Measurement System of Rolling Bearing Roundness

by Lei Zhao, Hui Chen, Jianzuo Ma, Chuanbing Wang and Lai Hu

J. Manuf. Mater. Process. 2026, 10(6), 211; https://doi.org/10.3390/jmmp10060211 - 16 Jun 2026

Viewed by 412

Abstract

High-precision rolling bearing applications are widely used in aerospace, new energy vehicles and high-end equipment. However, high-precision bearing manufacturing has always been one of the hot topics of research. The main problem is that the grinding accuracy of rolling bearings is too divergent. [...] Read more.

High-precision rolling bearing applications are widely used in aerospace, new energy vehicles and high-end equipment. However, high-precision bearing manufacturing has always been one of the hot topics of research. The main problem is that the grinding accuracy of rolling bearings is too divergent. In this study, the improvement of grinding accuracy of high-precision rolling bearings was mainly studied. An on-line roundness measurement system was developed and its accuracy was analyzed. The same bearing precision grade, different bearing brands, different bearing sizes and different measurement methods were mainly used for cross-precision measurement comparison. Meanwhile, a static analysis was conducted on the measuring claw. Results indicate that the on-line measurement system can achieve an accuracy of 3 µm. The error rate was less than 11% compared with the current mature measurement technology. Under the action of the same normal measuring force, the deformation of the measuring claw of invar was larger than that of the measuring claw of 45 steel, which was relatively increased by 31%. The conclusion of this study will provide reliable data analysis and a theoretical basis for research in the field of bearing. Full article

(This article belongs to the Special Issue Next-Generation Machine Tools and Machining Technology)

► Show Figures

Figure 1

19 pages, 21746 KB

Open AccessArticle

Influence of Deposition Strategy and Fiber Alignment on the Mechanical Anisotropy of Short-Fiber-Reinforced Polyamide Manufactured by Additive Manufacturing Material Extrusion

by Andrea Colucci, Manuela Galati and Luca Iuliano

J. Manuf. Mater. Process. 2026, 10(6), 210; https://doi.org/10.3390/jmmp10060210 - 16 Jun 2026

Viewed by 666

Abstract

Short-fiber-reinforced composites (SFRCs) are widely used for their high strength-to-weight ratio. In the Additive Manufacturing (AM) field, Material Extrusion (MEX) processes inherently induce anisotropy, primarily due to fiber alignment along the deposition path, making printing direction and layer orientation critical for mechanical performance. [...] Read more.

Short-fiber-reinforced composites (SFRCs) are widely used for their high strength-to-weight ratio. In the Additive Manufacturing (AM) field, Material Extrusion (MEX) processes inherently induce anisotropy, primarily due to fiber alignment along the deposition path, making printing direction and layer orientation critical for mechanical performance. In this study, specimens made of Onyx^®, a carbon short-fiber-reinforced polyamide, were fabricated by varying their orientation on the build platform, thereby producing different infill deposition directions. Each replica contained 25 layers. Two deposition strategies were investigated: a conventional alternating ±45° raster pattern and a 0°/90° configuration. Owing to the odd number of deposited layers, the latter resulted in two distinct stacking configurations, namely 0°/90° and 90°/0°, depending on the orientation of the first deposited layer. With such a strategy, it was possible to obtain configurations with a predominance of fibers either aligned with or transverse to the loading direction, depending on the orientation of the first-deposited layer. Mechanical test results were systematically compared to evaluate the influence of deposition strategy and fiber orientation on tensile performances. The effect of extrusion on fiber alignment was evaluated using Scanning Electron Microscopy (SEM). Mechanical behavior was evaluated using replicated tensile testing (five specimens per condition) and SEM-based fiber-orientation analysis. The investigation confirms the anisotropic nature of MEX-produced SFRCs. In particular, the 0°/90° configuration showed reductions of approximately 24% in tensile strength and 58% in elongation at break compared with the ±45° configuration. These results demonstrate that both extrusion-induced fiber orientation and layer-wise deposition strategy play a crucial role in defining the mechanical response of the material. Full article

(This article belongs to the Special Issue Processing, Mechanical Properties, and Manufacturing Techniques of Advanced Composite Materials)

► Show Figures

Figure 1

22 pages, 25117 KB

Open AccessArticle

Energy Efficiency-Driven Selection of Wireless Communication Stacks for Industrial Retrofitting Applications

by Richárd Korpai, Norbert Szántó and Gergő Dávid Monek

J. Manuf. Mater. Process. 2026, 10(6), 209; https://doi.org/10.3390/jmmp10060209 - 16 Jun 2026

Viewed by 507

Abstract

The digital integration of existing industrial equipment (retrofitting) is a central element of the Industry 4.0 paradigm, wherein the energy efficiency of Internet of Things (IoT) gateways is a decisive design consideration. This research aims to experimentally compare various wireless and wired communication [...] Read more.

The digital integration of existing industrial equipment (retrofitting) is a central element of the Industry 4.0 paradigm, wherein the energy efficiency of Internet of Things (IoT) gateways is a decisive design consideration. This research aims to experimentally compare various wireless and wired communication protocols—ESP-NOW, Bluetooth Low Energy (BLE), Bluetooth Classic (Serial Port Profile, SPP), Message Queuing Telemetry Transport (MQTT), and S7 Protocol—within a legacy Programmable Logic Controller (PLC)-based environment. A dedicated testbed was developed using Siemens S7-300 PLCs and ESP32-based gateway devices to ensure measurement reproducibility. Energy consumption was determined using a high-precision power profiler with payloads ranging from 50 to 15,000 bytes, applying the trapezoidal rule while considering both active transaction and standby states. The specific energy consumption metric (μJ/byte) introduced in this study highlights the distinct scaling limitations of the protocols. While ESP-NOW proved highly efficient for small telemetry packets, Bluetooth Classic exhibited superior scalability for bulk data volumes. Furthermore, a critical energetic crossover point was identified for ESP-NOW due to hardware fragmentation limits, whereas MQTT demonstrated massive energetic overhead for small payloads. Standby measurements confirmed that the continuous baseline consumption of the wired Ethernet interface significantly dominates the energy budget compared to wireless alternatives. These empirical findings are synthesized into a formal Qualitative Decision Matrix to help engineers optimize protocol selection based on the expected duty cycle, facilitating the development of sustainable industrial digitalization solutions. Full article

► Show Figures

Figure 1

20 pages, 11996 KB

Open AccessArticle

Effect of Sintering Temperature and Artificial Aging on the Microstructure and Mechanical Properties of AlSi10Mg Alloy

by Mohamed Khaled Trigui, Alena Kreitcberg, Abdelberi Chandoul, Roger Pelletier and Vincent Demers

J. Manuf. Mater. Process. 2026, 10(6), 208; https://doi.org/10.3390/jmmp10060208 - 15 Jun 2026

Viewed by 596

Abstract

This study investigates the correlation between sintering temperature, microstructure, and mechanical properties in AlSi10Mg alloy produced by supersolidus liquid phase sintering and subsequent artificial aging. Sintering was performed at 571, 575, and 579 °C using different heating rates for a total duration of [...] Read more.

This study investigates the correlation between sintering temperature, microstructure, and mechanical properties in AlSi10Mg alloy produced by supersolidus liquid phase sintering and subsequent artificial aging. Sintering was performed at 571, 575, and 579 °C using different heating rates for a total duration of approximately 5 h, followed by a 2 h dwell at the sintering temperature. At low sintering temperature, the alloy exhibits relatively fine α-Al grains with uniformly distributed Si precipitates, whereas intermediate temperature promotes Si coarsening. At higher temperature, excessive liquid formation leads to coarse α-Al grains and the development of partially interconnected Si networks. β-Al₅FeSi progressively coarsen with increasing sintering temperature. In the as-sintered state, the modest mechanical properties result from coarse α-Al grain size and subgrain structure, as well as from the size, morphology, and distribution of the Si phase. After aging (at 160 °C for 6 h following solution treatment at 530 °C for 30 min), the hardness and UTS were almost double (going from 44 ± 1 to 103 ± 2 HV and from 121 ± 1 to 273 ± 40 MPa). Meanwhile, α-Al grain size and Si morphology remained unchanged and Fe-rich intermetallics partially transformed into the more stable γ-Al₃FeSi₂ phase. Full article

► Show Figures

Figure 1

15 pages, 3948 KB

Open AccessArticle

Machine Learning-Based Analysis of Elastic Springback in Bending of SS, Al, and Cu Sheets with Localized Heating

by Naser A. Alsaleh

J. Manuf. Mater. Process. 2026, 10(6), 207; https://doi.org/10.3390/jmmp10060207 - 14 Jun 2026

Viewed by 635

Abstract

Elastic springback is a critical challenge in sheet metal bending that directly affects dimensional accuracy and manufacturing efficiency. This study presents a comparative experimental and machine learning-based analysis of elastic springback behavior in three widely used sheet metals like stainless steel, aluminum, and [...] Read more.

Elastic springback is a critical challenge in sheet metal bending that directly affects dimensional accuracy and manufacturing efficiency. This study presents a comparative experimental and machine learning-based analysis of elastic springback behavior in three widely used sheet metals like stainless steel, aluminum, and copper, which are subjected to folding bending. The influence of key process parameters, namely sheet thickness (0.5 to 1.5 mm) and bending temperature (room temperature to 200 °C), was systematically examined under cold working. A cost-effective localized heating approach using a direct flame was introduced to enhance process control and reduce elastic recovery without the complexity associated with heated dies. Experimental results revealed substantial variability in elastic springback, ranging from 0.15% to 12.41%, emphasizing the fact that they are nonlinear in nature. Statistical evaluation confirmed that sheet thickness is the dominant factor governing elastic springback, while material type and temperature exhibit secondary yet meaningful effects. To improve predictive capability, five regression models (Linear, Polynomial, Support Vector, Random Forest, and Gradient Boosting) were developed and assessed. Among them, Random Forest demonstrated superior performance with the lowest prediction errors and strongest explanatory power, achieving an R² of approximately 0.85. Cross-validation further validated its robustness and generalization capability. Feature importance and SHapley Additive exPlanations (SHAP) analyses reinforced the primary role of thickness in determining elastic recovery behavior. The findings provide practical insights for selecting materials and process conditions to minimize elastic springback while highlighting the effectiveness of ensemble learning techniques for accurate prediction. This work contributes a consistent framework for enhancing bending precision and supports data-driven decision-making in modern manufacturing environments. Full article

► Show Figures

Figure 1

19 pages, 9056 KB

Open AccessArticle

Dynamic Modeling and Chatter Stability of a Robotic Milling Manipulator Considering the Flexibility of Arms and Joints

by Chao Chen, Jingjun Yu, Yiqing Yang, Wenjing Wu and Wenshuo Ma

J. Manuf. Mater. Process. 2026, 10(6), 206; https://doi.org/10.3390/jmmp10060206 - 14 Jun 2026

Viewed by 610

Abstract

The application of robotic milling manipulators demonstrates a promising method for the efficient manufacturing of large-scale structures. However, the cutting accuracy and efficiency of milling robots are predominantly subjected to their low stiffness, which may easily cause chatter during machining. Accurate prediction of [...] Read more.

The application of robotic milling manipulators demonstrates a promising method for the efficient manufacturing of large-scale structures. However, the cutting accuracy and efficiency of milling robots are predominantly subjected to their low stiffness, which may easily cause chatter during machining. Accurate prediction of chatter stability for robots is of practical importance and is challenging. This paper develops a dynamic model of flexible link elements by considering link flexibility and joint torsional deformation and then constructs a multi-link flexible coupled dynamic model using the receptance coupling substructure analysis (RCSA) method. Subsequently, the equivalent dynamic parameters are identified via the particle swarm optimization (PSO) algorithm. On this basis, the end-effector frequency response functions (FRFs) of the robot under different poses are predicted, and the stability lobe diagram (SLD) for milling is generated based on chatter theory. Finally, the predicted FRFs and stability regions are validated through modal tests and milling experiments. Experimental results demonstrate that the proposed model can predict the end-effector dynamic characteristics and chatter occurrence conditions under different poses, confirming its effectiveness in the analysis of milling chatter stability. Quantitative validation yields a maximum error of 3% for predicted first-order modal frequencies and relative modal amplitude errors below 10%, with experimentally confirmed critical depths of cut of 0.1–0.2 mm at 3000 rev/min and 0.5–0.6 mm at 5000 rev/min. Full article

► Show Figures

Figure 1

22 pages, 20244 KB

Open AccessArticle

Microstructural Evolution and Mechanical Behavior of L-PBF Al-Cu 224 Alloy: Role of Process Parameters and Heat Treatment

by Esmaeil Pourkhorshid, Paul Rometsch, Mousa Javidani, Alexandre Bily and X.-Grant Chen

J. Manuf. Mater. Process. 2026, 10(6), 205; https://doi.org/10.3390/jmmp10060205 - 12 Jun 2026

Viewed by 769

Abstract

This study investigates the effect of laser powder bed fusion (L-PBF) parameters and T7 heat treatment on the defect formation, microstructure, and mechanical properties of a high-strength Al-Cu 224 aluminum alloy. The laser power (200–370 W), scanning speed (130–1900 mm/s), and hatch spacing [...] Read more.

This study investigates the effect of laser powder bed fusion (L-PBF) parameters and T7 heat treatment on the defect formation, microstructure, and mechanical properties of a high-strength Al-Cu 224 aluminum alloy. The laser power (200–370 W), scanning speed (130–1900 mm/s), and hatch spacing (90–130 μm) were varied to evaluate their influence on hot cracking and porosity. Microstructural characterization using optical microscopy, scanning electron microscopy, and electron backscatter diffraction revealed that an energy density of 400 J/mm³ substantially reduced visible hot cracking in the examined microscopic regions by reducing the thermal gradients. However, this resulted in increased keyhole porosity, thereby limiting the relative density to 95%. The as-built samples exhibited a yield strength of 152 MPa and an elongation of 9.2%, and the T7 heat treatment improved the yield strength to 233 MPa, whereas the elongation remained unchanged. Keyhole pores served as primary crack initiation/propagation sites during tensile loading, reducing ductility. Lower energy densities increased the geometrically necessary dislocation density and promoted cracking because of higher residual stresses due to greater accumulated plastic strain and lattice curvature. These results clarify process–structure–property relationships, emphasize the trade-offs between defect types and performance, and provide a robust framework for optimizing L-PBF processing of high-strength Al alloys through parameter tuning and post-heat treatment. Full article

(This article belongs to the Special Issue Recent Progress and Scientific Challenges in Laser-Based Additive Manufacturing)

► Show Figures

Figure 1

29 pages, 28942 KB

Open AccessArticle

Development of a Launch Mechanism for Small Satellites Using Laser Powder Bed Fusion Process

by Cosmin Gogu, Cătălin-Gheorghe Amza and Cristina Pupăză

J. Manuf. Mater. Process. 2026, 10(6), 204; https://doi.org/10.3390/jmmp10060204 - 11 Jun 2026

Viewed by 678

Abstract

The deployment of CubeSats requires reliable, lightweight, and space-efficient launch mechanisms. Traditional spring-based deployers often rely on standard off-the-shelf components, limiting the design flexibility. This study presents a pilot design-to-verification workflow for a CubeSat deployment mechanism manufactured by Laser Powder Bed Fusion from [...] Read more.

The deployment of CubeSats requires reliable, lightweight, and space-efficient launch mechanisms. Traditional spring-based deployers often rely on standard off-the-shelf components, limiting the design flexibility. This study presents a pilot design-to-verification workflow for a CubeSat deployment mechanism manufactured by Laser Powder Bed Fusion from 316L stainless steel. The workflow integrates analytical sizing, kinematic and numerical force assessment, FEM-based LPBF process simulation employed as a design-support tool to predict thermal displacements and residual stress that occur during manufacturing, prototype manufacturing and optical inspection. Optical scanning indicated that the main envelope dimensions remained close to the nominal CAD values, while the support-plate warping was localized at the plate corners due to the residual thermal stress after the support removal. The study validates the manufacturability of a single LPBF orbital-deployer lunch mechanism and assesses its dimensional accuracy and workflow feasibility, rather than its functional mechanical performance. It also includes mitigation strategies for deployer distortions. Full article

► Show Figures

Figure 1

28 pages, 9487 KB

Open AccessArticle

Multi-Objective Optimization of a Composite FRP Laminated Sandwich Structure Using Artificial Neural Network and Particle Swarm Optimization Algorithm

by Muhammad Ali Sadiq and György Kovács

J. Manuf. Mater. Process. 2026, 10(6), 203; https://doi.org/10.3390/jmmp10060203 - 11 Jun 2026

Viewed by 764

Abstract

Designing lightweight composite sandwich structures is challenging due to the conflicting objectives of minimizing structural weight and cost while satisfying strength and stiffness requirements. The optimization procedure becomes more complex when multiple discrete design variables and nonlinear material behavior are involved. This study [...] Read more.

Designing lightweight composite sandwich structures is challenging due to the conflicting objectives of minimizing structural weight and cost while satisfying strength and stiffness requirements. The optimization procedure becomes more complex when multiple discrete design variables and nonlinear material behavior are involved. This study presents a newly developed optimization methodology for a sandwich structure composed of Fiber Reinforced Polymer (FRP) laminated facesheets and an aluminum honeycomb core. To reduce the computational cost associated with repeated high-fidelity Finite Element (FE) analyses, a surrogate modeling strategy based on Artificial Neural Networks (ANNs) is employed to approximate the structural response. The applied dataset is generated using Monte Carlo simulation in which combinations of design variables are used as inputs, and the corresponding structural responses obtained from the analytical formulation are used as outputs for training the ANN surrogate model. The trained ANN model is integrated with a Multi-Objective Niching Memetic Particle Swarm Optimization (MO-NMPSO) algorithm to simultaneously minimize structural weight and material cost while satisfying constraints on facesheet strength, wrinkling, intra-cell buckling, deflection, core shear failure and structural thickness. The resulting Pareto-optimal solutions are validated through detailed FE simulations, demonstrating the reliability of the newly elaborated optimization framework. The results of the newly developed computationally efficient optimization procedure provide a diverse set of optimal design solutions for the investigated sandwich structure. Full article

(This article belongs to the Special Issue Processing, Mechanical Properties, and Manufacturing Techniques of Advanced Composite Materials)

► Show Figures

Figure 1

26 pages, 4784 KB

Open AccessArticle

Microstructural Diversity in Dispersed Composites Governed by Inclusion Distribution

by Vladimir Mityushev, Pawel Kurtyka, Zhanat Zhunussova and Akylkerey Sarvarov

J. Manuf. Mater. Process. 2026, 10(6), 202; https://doi.org/10.3390/jmmp10060202 - 10 Jun 2026

Viewed by 618

Abstract

The microstructure of metal matrix composites is inherently governed by fabrication routes and processing parameters, yet technological and physical constraints often prevent the realization of intended structural designs. In particle-reinforced composites produced via casting, interactions between the solidification front and inclusions frequently lead [...] Read more.

The microstructure of metal matrix composites is inherently governed by fabrication routes and processing parameters, yet technological and physical constraints often prevent the realization of intended structural designs. In particle-reinforced composites produced via casting, interactions between the solidification front and inclusions frequently lead to agglomeration, segregation, and hence, a non-uniform distribution of the inclusions concentration. To mitigate these effects, post-processing techniques such as Friction Stir Processing offering particular promise for cast materials by refining microstructures and enhancing phase homogeneity. This study addresses these challenges by application of Fourier transform analysis to characterize stochastic inclusion distributions. Building on the Windows Washing method, we extend its application to heterogeneous media with varying inclusion concentrations. Through computer simulations and experimental analysis of real composites, we demonstrate that discrete Fourier transform can reveal hidden stochastic periodicity. The proposed framework provides a pathway toward improved predictive models and optimization strategies for metal matrix composites processing and performance. Full article

(This article belongs to the Special Issue Processing, Mechanical Properties, and Manufacturing Techniques of Advanced Composite Materials)

► Show Figures

Figure 1

21 pages, 5558 KB

Open AccessArticle

Sustainable 3D Printing of Recycled PET: Influence of Infill Architecture and Layer Thickness on Mechanical Behavior

by Rahmat Doni Widodo, Muhammad Irfan Nuryanta and Muhammad Akhsin Muflikhun

J. Manuf. Mater. Process. 2026, 10(6), 201; https://doi.org/10.3390/jmmp10060201 - 8 Jun 2026

Viewed by 892

Abstract

The utilization of polyethylene terephthalate (PET) waste from single-use packaging offers potential for sustainable manufacturing. This study evaluates recycled PET (rPET) from bottles as an FDM filament by varying infill architectures (honeycomb, gyroid, grid, and triangles) and layer thicknesses (0.20, 0.25, and 0.30 [...] Read more.

The utilization of polyethylene terephthalate (PET) waste from single-use packaging offers potential for sustainable manufacturing. This study evaluates recycled PET (rPET) from bottles as an FDM filament by varying infill architectures (honeycomb, gyroid, grid, and triangles) and layer thicknesses (0.20, 0.25, and 0.30 mm), with commercial PETG as a benchmark. Compared with previous rPET FDM studies, which were limited to reporting mechanical strength, the novelty of this study lies in the fact that it not only reports mechanical strength performance, but also compares printing time requirements and material efficiency. Efficiency calculations are obtained by comparing the weight of the filament to the weight of the printed specimen, which then correlates with optimizing processing time and costs. Overall, rPET produced densities of 1.11–1.22 g/cm³, tensile strengths of 12.5–22.5 MPa, flexural strengths of 12.5–30 MPa, impact strengths of 0.032–0.060 J/mm², and surface roughnesses of Ra 5.2–7.1 μm, while PETG showed higher mechanical performance (tensile 30–39.5 MPa, flexural 30–50 MPa, impact 0.037–0.065 J/mm²) and comparable density (1.15–1.27 g/cm³). Within rPET, gyroid provided the best optimal performance; the gyroid (0.20 mm) variation achieved the highest impact response (0.060 J/mm²) and the lowest Ra (5.2 μm) and the gyroid (0.25 mm) variation maximized flexural strength (30 MPa) and the gyroid (0.30 mm) variation maximized tensile strength (22.5 MPa). Material utilization efficiency was consistently higher for rPET (65–68%) than for PETG (46–56%). These results provide an integrated rPET-specific assessment and practical parameter recommendations for functional 3D printing, while also aligning with SDG 12 by pro-moting resource-efficient circular-economy practices through the utilization of waste materials in additive manufacturing. Full article

► Show Figures

Figure 1

16 pages, 16748 KB

Open AccessArticle

Roll Bonding of Aluminium Coupons Using the Established Fully Fledged Offline Fabrication Facilities

by Joseph Moema, Charles Siyasiya, Veronica Morudu, Maje Phasha and Mbavhalelo Maumela

J. Manuf. Mater. Process. 2026, 10(6), 200; https://doi.org/10.3390/jmmp10060200 - 8 Jun 2026

Viewed by 464

Abstract

The South African aluminium industry faces technical challenges related to cladded ingots used in automotive heat exchangers, creating a need for offline processing methods that can replicate rolling processes like roll bonding, as large-scale industrial trials are costly and difficult to control. To [...] Read more.

The South African aluminium industry faces technical challenges related to cladded ingots used in automotive heat exchangers, creating a need for offline processing methods that can replicate rolling processes like roll bonding, as large-scale industrial trials are costly and difficult to control. To address this, Mintek established a comprehensive offline manufacturing facility for process and product development of rolled metal products, focusing on the thermomechanical processing of aluminium alloys. In this study, stacked AA4045/AA3003mod coupons were processed under controlled conditions by varying thickness reduction, temperature, and reheating, aiming to investigate the effect of isothermal soaking time on microstructure and mechanical properties. Tensile tests were performed on clad sheets before and after brazing heat treatment, and fracture surfaces were examined via scanning electron microscopy. Samples heated at 505 °C for ≥38 h, followed by cold rolling and annealing, fell at the lower end of the 9031-H24 specification for yield strength, which is important for this application (i.e., the minimum tensile yield strength of 145 MPa and the ultimate tensile strength (UTS) range of 190 to 230 MPa). Fracture surface analysis revealed a dimple-dominated structure in cold-rolled and annealed samples, indicating ductile fracture. The study concludes that the offline roll-bonding method successfully replicates industrial cladding processes, and that isothermal soaking duration significantly influences mechanical performance, though careful control of thermal exposure is necessary to meet the specified mechanical properties. Full article

(This article belongs to the Topic Advances in Processing, Microstructure and Mechanical Properties of Lightweight Alloys)

► Show Figures

Figure 1

17 pages, 10205 KB

Open AccessArticle

Mechanical and Thermal Performance of Sustainable PETG/Cork Composites Processed by Fused Filament Fabrication Technology

by Saltanat Bergaliyeva, Daniel Correro-Cabrera, Ismael Romero-Ocaña, Nuria Baladés, Natalia Fernández Delgado, Sergio I. Molina and David L. Sales

J. Manuf. Mater. Process. 2026, 10(6), 199; https://doi.org/10.3390/jmmp10060199 - 8 Jun 2026

Viewed by 654

Abstract

Despite major advances in polymer composites for Fused Filament Fabrication (FFF), designing environmentally sustainable materials from bio-based resources remains a key research priority. The objective of this study is to check the processability and properties of sustainable PETG/cork composites processed via FFF technology. [...] Read more.

Despite major advances in polymer composites for Fused Filament Fabrication (FFF), designing environmentally sustainable materials from bio-based resources remains a key research priority. The objective of this study is to check the processability and properties of sustainable PETG/cork composites processed via FFF technology. Filaments with 5 and 10% of cork were created using a twin-screw extruder. Samples from these filaments were printed by FFF technology, and subsequently subjected to morphological, thermal and mechanical testing. As a result of the study, it was proved that the 3D-printing process did not result in a tensile strength decrease with an increasing cork percentage, as observed in mechanical testing of the filament. The addition of cork significantly increased plasticity without decreasing tensile strength when introducing 10% of cork particles. The interfacial temperatures of the prepared composites did not differ much from the polymer matrix and were 79.55 °C, 77.56 °C, 76.67 °C for PET-G, PET-G + 5% cork, and PET-G + 10% cork, respectively. Thermal conductivity decreased significantly as the percentage of cork increased. This work shows that FFF technology is one of the most suitable manufacturing options for PETG + 10% cork composites to produce things with low conductivity and the same thermal and mechanical properties as pure PETG. Full article

(This article belongs to the Special Issue Innovative and Sustainable Advances in Polymer Composites for Additive Manufacturing: Processing, Microstructure, Machining, and Mechanical Properties)

► Show Figures

Figure 1

19 pages, 9330 KB

Open AccessArticle

Manufacturing of 3D Auxetic Structures Through Perforations of Corrugated Systems

by Libera Vitiello, Gianluca Cicala, Giovanni Filippone, Pietro Russo, Ruben Gatt, Joseph N. Grima and Pierre-Sandre Farrugia

J. Manuf. Mater. Process. 2026, 10(6), 198; https://doi.org/10.3390/jmmp10060198 - 4 Jun 2026

Viewed by 880

Abstract

Fabrication of auxetic structures has always been a limiting factor in their availability. Their complex shape, a requirement originating from the deformation mechanism that leads to a negative Poisson’s ratio, has also limited their manufacturability. In the case of auxetic systems that deform [...] Read more.

Fabrication of auxetic structures has always been a limiting factor in their availability. Their complex shape, a requirement originating from the deformation mechanism that leads to a negative Poisson’s ratio, has also limited their manufacturability. In the case of auxetic systems that deform through the rotating semi-rigid mechanism—which allows for the concurrent deformation and rotation of their constituent element—the situation is even more complicated. Relatively few examples of these types of structures are known, with most work on them being largely theoretical. This includes their use in explaining the auxetic mechanism in certain molecules. Nevertheless, these systems can, in principle, offer added functionalities, as they undergo a shape change while still exhibiting a negative Poisson’s ratio. To this end, this work presents a practical scheme for the manufacturing of 3D rotating semi-rigid units, whereby these are produced through perforations of corrugated sheets. For the purpose of this investigation, diamond-shaped perforations were chosen, and the side profile of the corrugated sheet consisted of successive semicircles that alternate in orientation. Analysis of the system indicated that a 3D negative Poisson’s ratio can be obtained while allowing the distance between the hinges to change during deformation. Full article

► Show Figures

Graphical abstract

18 pages, 9138 KB

Open AccessArticle

Design and Computational Efficiency of a GPU-Resident Integrated Execution Pipeline for Explicit Large-Deformation Finite Element Analysis

by Honglae Kim, Seokmoo Hong and Naksoo Kim

J. Manuf. Mater. Process. 2026, 10(6), 197; https://doi.org/10.3390/jmmp10060197 - 3 Jun 2026

Viewed by 528

Abstract

We describe a GPU-resident execution pipeline for explicit large-deformation finite element analysis in which every stage of the timestep—internal force evaluation, contact processing, nodal update, time integration, and minimum edge-length reduction—operates on arrays that remain in device memory, so per-step bulk transfers across [...] Read more.

We describe a GPU-resident execution pipeline for explicit large-deformation finite element analysis in which every stage of the timestep—internal force evaluation, contact processing, nodal update, time integration, and minimum edge-length reduction—operates on arrays that remain in device memory, so per-step bulk transfers across PCIe are avoided. Contact is handled on the device through a shared-memory brute-force proximity search with warp-ballot stream compaction. We exercise the solver on a hemisphere compression benchmark at six mesh resolutions (83 K–1.89 M elements). On an NVIDIA L40, per-step speedups over a single CPU core range from about 99× to 138×, increasing with problem size and approaching a plateau near 137× for the largest meshes (above roughly 1 M elements); the contact-enabled configuration adds a net ON/OFF overhead of +13% to +21% to the step time. Against LS-DYNA running in SMP mode on the same problem, the proposed solver is roughly 94× faster than the best 8-core configuration, a margin consistent with the multicore saturation observed in the SMP measurements. The remaining limitations—single-GPU execution, FP32 arithmetic, and rigid-body contact search without a BVH broad phase—are identified as specific targets for multi-GPU, mixed-precision, and scalable-contact extensions. Full article

► Show Figures

Figure 1

19 pages, 35766 KB

Open AccessArticle

Synergistic Strengthening of Copper by In Situ Graphene Growth and Severe Plastic Deformation

by Junaid Dar, Laxman Bhatta, Islam Hafez, Megumi Kawasaki and Dong Lin

J. Manuf. Mater. Process. 2026, 10(6), 196; https://doi.org/10.3390/jmmp10060196 - 2 Jun 2026

Viewed by 797

Abstract

High-purity copper features excellent electrical conductivity but generally low mechanical properties. Adding a three-dimensional graphene network as reinforcement to make a copper–graphene metal matrix composite is promising for a wide range of applications with better mechanical performance and functional capabilities. However, direct application [...] Read more.

High-purity copper features excellent electrical conductivity but generally low mechanical properties. Adding a three-dimensional graphene network as reinforcement to make a copper–graphene metal matrix composite is promising for a wide range of applications with better mechanical performance and functional capabilities. However, direct application in a metal matrix is difficult due to unfavorable wetting, which causes poor dispersion and weak interfacial bonding in the graphene–metal system. Here, the powder metallurgy method was used to construct a three-dimensional continuous graphene network in the copper matrix combined with high-pressure torsion. Optimized deformation/thermomechanical treatment enhanced the microstructural development processed by the severe plastic deformation method of high-pressure torsion. The primary advantage of this hybrid process is that it enables us to achieve grains with a size in the ultra-fine or even nanoscale. A homogeneous equiaxed nanostructure without segregation was observed during microstructural characterization, with a grain size of ~300 nm. This study investigated structural development during progressive deformation, and the samples were evaluated from the viewpoint of grain size and grain boundaries. The process significantly increased the microhardness of the copper–graphene composite. The tensile strength reached ~500 MPa at room temperature. The interpenetrating structural feature of graphene promoted interfacial shear stress to a high level, whereas plastic deformation increased the dislocation density and grain boundaries, thus resulting in significantly enhanced load transfer strengthening and crack-bridging toughness simultaneously. Full article

► Show Figures

Graphical abstract

24 pages, 41455 KB

Open AccessReview

An Overview of Plastic Deformation Preparation Methods and Application of Gradient-Structured Materials

by Zhenhai Xu, Jiajia Wang, Shaoxi Xue, Debin Shan, Jie Xu and Bin Guo

J. Manuf. Mater. Process. 2026, 10(6), 195; https://doi.org/10.3390/jmmp10060195 - 31 May 2026

Viewed by 478

Abstract

Gradient-structured materials have attracted considerable attention due to their gradient microstructural distribution and the resulting unique mechanical properties, showing great potential in aerospace, marine, and energy applications. This review presents a comprehensive overview of plastic deformation methods for fabricating gradient-structured materials, according to [...] Read more.

Gradient-structured materials have attracted considerable attention due to their gradient microstructural distribution and the resulting unique mechanical properties, showing great potential in aerospace, marine, and energy applications. This review presents a comprehensive overview of plastic deformation methods for fabricating gradient-structured materials, according to the loading conditions and resulting deformation modes, which are categorized into localized loading-localized deformation, localized loading-localized/global deformation, and global loading-localized/global deformation strategies. The applications of gradient-structured materials are further summarized in terms of surface properties, bulk mechanical properties, and forming performance. Finally, the current challenges and future research directions are discussed, focusing on quantitative structure-property relationships for inverse design, efficient and scalable fabrication strategies, and the synergistic effects of multi-level microstructures. This review offers significant insights into plastic-deformation-based fabrication methods and the diverse application properties of gradient-structured materials. Full article

(This article belongs to the Topic Advances in Manufacturing and Mechanics of Materials)

► Show Figures

Figure 1

24 pages, 6830 KB

Open AccessArticle

A Numerical and Experimental Analysis of Large Interference Fitting Cylinders

by Iñigo Llavori, Alaitz Zabala, Joseba Mendiguren, Xuban Telleria, Nagore Otegi and Eneko Saenz-de-Argandoña

J. Manuf. Mater. Process. 2026, 10(6), 194; https://doi.org/10.3390/jmmp10060194 - 31 May 2026

Viewed by 712

Abstract

This research analyses the mechanical behaviour of the insertion process between two cylinders that are commonly employed in non-rigid joints. Through comprehensive analysis, the study reveals the dynamics of insertion force, particularly by highlighting the impact of initial collisions on subsequent deformations and [...] Read more.

This research analyses the mechanical behaviour of the insertion process between two cylinders that are commonly employed in non-rigid joints. Through comprehensive analysis, the study reveals the dynamics of insertion force, particularly by highlighting the impact of initial collisions on subsequent deformations and the ultimate evolution of insertion forces. Contrary to intuitive assumptions, our findings reveal that higher interference levels between cylinders do not uniformly correlate with increased maximum insertion force levels; instead, for certain cylinder combinations, higher interference generates lower maximum insertion force levels. Additionally, the significance of the thickness ratio as a pivotal determinant in predicting overall behaviour and insertion force, which is a variable that is often overlooked in conventional analyses, has been underscored. Furthermore, it has been demonstrated that the applicability of analytical equations that were developed as part of thick-walled cylinder theory diminishes when mechanical joints undergo plasticity, which underscores the need for alternative modelling approaches. Through finite element simulations, fidelity when representing insertion processes, with errors below 15%, not only capturing peak insertion forces but also delineating the nuanced evolution of forces and cylinder deformations, has been attained. Conversely, the analytical method employed from the examined literature yielded unrealistic insertion force estimations that proved inadequate for scenarios that involve substantial interference. Full article

(This article belongs to the Topic Advances in Manufacturing and Mechanics of Materials)

► Show Figures

Figure 1

21 pages, 11811 KB

Open AccessArticle

Deep CNN-Based Multi-Class TIG Welding Defect Classification Using HDR Images with Explainable AI

by Deepika Nikam, Sagar Nikam, Tejaswini Bhosale, Declan Harkin, Mayur Sawant and Cormac McGarrigle

J. Manuf. Mater. Process. 2026, 10(6), 193; https://doi.org/10.3390/jmmp10060193 - 30 May 2026

Viewed by 1061

Abstract

Recent advances in deep convolutional neural networks (D-CNNs) have improved automated welding defect inspection. This study presents an explainable comparative framework for multi-class classification of defects in Aluminium 5083 TIG weld joints using High Dynamic Range (HDR) image data, integrating a transfer-learning model, [...] Read more.

Recent advances in deep convolutional neural networks (D-CNNs) have improved automated welding defect inspection. This study presents an explainable comparative framework for multi-class classification of defects in Aluminium 5083 TIG weld joints using High Dynamic Range (HDR) image data, integrating a transfer-learning model, stratified five-fold cross-validation, computational-time analysis, and Grad-CAM-based visual interpretation. Five transfer-learning-based D-CNN architectures such as VGG16, VGG19, Inception V3, MobileNet, and DenseNet were trained, validated, and tested under a common evaluation protocol to assess their suitability for welding defect classification. The dataset was organised into classes such as good weld, contamination, lack of fusion, lack of penetration, and misalignment. Model performance was compared using multiple evaluation metrics. Stratified five-fold cross-validation was also performed to assess model stability. Alongside the cross-validation, training/inference times were also recorded to evaluate computational feasibility. Grad-CAM was used as an explainable artificial intelligence (XAI) technique in order to provide visual interpretation of weld regions. Among evaluated models, DenseNet achieved the best overall performance, with a classification accuracy of 98%, and showed the least confusion across defect classes. The Grad-CAM visualisations showed that the model focused on defect-relevant weld regions, demonstrating that transfer-learning D-CNNs with XAI can support TIG welding defect classification and effective visual quality assessment. Full article

► Show Figures

Figure 1

14 pages, 912 KB

Open AccessArticle

Comparative Life Cycle Assessment of Hull Manufacturing for Small-Size Crafts

by Paolo De Sio, Vittorio Rosanova, Vitantonio Esperto, Antonello Astarita and Fausto Tucci

J. Manuf. Mater. Process. 2026, 10(6), 192; https://doi.org/10.3390/jmmp10060192 - 30 May 2026

Viewed by 625

Abstract

In recent years, environmental sustainability has become a key issue in the shipbuilding industry, driving research towards a reduction in the environmental impact throughout the entire life cycle of vessels. In this context, composite materials are a solid alternative to achieve mechanical performance [...] Read more.

In recent years, environmental sustainability has become a key issue in the shipbuilding industry, driving research towards a reduction in the environmental impact throughout the entire life cycle of vessels. In this context, composite materials are a solid alternative to achieve mechanical performance optimization and energy consumption reduction. This study compares two hull configurations, one in a glass fiber-reinforced thermoset composite and one in a thermoplastic composite sandwich structure, through life cycle assessment. The aim is to assess the influence of material choice and structural configuration on overall environmental impacts by analyzing energy and material inputs and emissions throughout the entire life cycle, from “cradle to grave” excluding the end-of-life treatment. The results evidence a 36% average reduction in the impact categories analyzed. Moreover, economic benefits emerged, with a 35% reduction in the cost of energy required during the analyzed life cycle phases and 9% reduction in the material supply. This work aims to contribute to the definition of more sustainable design strategies to produce hulls and naval components, promoting a transition towards a more efficient and environmentally friendly nautical sector. Full article

(This article belongs to the Special Issue Processing, Mechanical Properties, and Manufacturing Techniques of Advanced Composite Materials)

► Show Figures

Figure 1

18 pages, 52572 KB

Open AccessArticle

Machining-Induced Surface Deformation Layer and the Impact on Tensile Plasticity of 316L Stainless Steel

by Bokai Lou, Jing Ni, Jinghui Zhou, Lihua He, Zhenbing Cai and Zefei Zhu

J. Manuf. Mater. Process. 2026, 10(6), 191; https://doi.org/10.3390/jmmp10060191 - 29 May 2026

Viewed by 587

Abstract

316L stainless steel is widely used in aerospace components because of its mechanical properties and corrosion resistance. Standard tensile specimens are commonly used to evaluate material behavior, yet their measured tensile response can be affected by the final turning process. This study investigated [...] Read more.

316L stainless steel is widely used in aerospace components because of its mechanical properties and corrosion resistance. Standard tensile specimens are commonly used to evaluate material behavior, yet their measured tensile response can be affected by the final turning process. This study investigated the effects of cutting speed and depth of cut on the surface integrity and tensile properties of small standard 316L tensile specimens. Cutting-temperature measurement, optical surface characterization, EBSD analysis, fracture observation, and quasi-static tensile testing were combined to evaluate the machined specimens. A cutting speed of 45 m/min produced the most stable thermal response after repeated tool–workpiece contacts, with a temperature variation of 40.3%. Lower cutting speeds suppressed vibration-induced micro-pits and improved the morphology consistency between Area I and Area II. At the maximum depth of cut, increasing the cutting speed from 15 m/min to 60 m/min reduced the tensile strength from 1136.02 MPa to 1082.75 MPa and the tensile elongation from 56.6% to 53.5%. These results show that the tensile properties of turned specimens are governed by the combined effects of thermal response, surface morphology, deformation-layer microstructure, and fracture behavior. Among the tested conditions,

V_{c}

= 15 m/min,

a_{p}

= 0.4 mm, and

f

= 0.1 mm/rev are recommended when tensile properties are the main requirement. Full article

► Show Figures

Figure 1

33 pages, 1507 KB

Open AccessReview

Soil–Cement Mixtures with Fiber Reinforcement in 3D Printing: Challenges and Opportunities for Sustainable Construction

by Juan D. Trujillo, Sandra Villamizar and Daniel Gomez

J. Manuf. Mater. Process. 2026, 10(6), 190; https://doi.org/10.3390/jmmp10060190 - 29 May 2026

Viewed by 1162

Abstract

Additive manufacturing with soil–cement mixtures is emerging as a disruptive approach to advancing sustainable manufacturing processes. However, its industrial scalability remains limited by material brittleness and a lack of process standardization. This study presents an integrative literature review that critically evaluates the influence [...] Read more.

Additive manufacturing with soil–cement mixtures is emerging as a disruptive approach to advancing sustainable manufacturing processes. However, its industrial scalability remains limited by material brittleness and a lack of process standardization. This study presents an integrative literature review that critically evaluates the influence of fiber reinforcement on the 3D printing process and the mechanical performance of soil–cement mixtures within the context of sustainable construction and circular economy principles. The analysis integrates fresh-state rheological behavior with hardened-state performance, showing that an optimized fiber dosage (0.3–0.5% by volume) shifts the failure mode from brittle to quasi-ductile while reducing crack propagation by approximately 60%. Additionally, the study compares various fiber types, including synthetic and natural alternatives. The results show that synthetic fibers used at low dosages (0.5–1.0% by volume) provide the greatest improvements in tensile strength and post-cracking ductility. In contrast, natural fibers, typically used at higher dosages (8.0–13.0% by volume), mainly improve toughness and thermal performance, with more limited gains in strength. The review also identifies key gaps in the existing literature, such as a lack of standardized protocols for measuring process parameters and the need for studies that address long-term durability and comprehensive lifecycle assessments. These findings outline a clear research roadmap to support the consolidation of reinforced soil–cement as a resilient and sustainable material for next-generation additive manufacturing. Full article

(This article belongs to the Special Issue Application of 3D Printing Technology in Manufacturing and Material Processing)

► Show Figures

Figure 1

16 pages, 5865 KB

Open AccessArticle

Thermal and Athermal Effects of High-Density Pulsed Electric Current on Strain-Hardening Relief in Cold-Rolled A6061 Under Liquid Nitrogen

by Shaojie Gu, Xiaoming Yu, Yanhong Peng, Lusheng Wang, Sungmin Yoon, Yi Cui, Yasuhiro Kimura, Yasuyuki Morita, Yuhki Toku and Yang Ju

J. Manuf. Mater. Process. 2026, 10(6), 189; https://doi.org/10.3390/jmmp10060189 - 29 May 2026

Viewed by 592

Abstract

Understanding the respective roles of thermal and athermal effects during electric current treatment is critical for advancing current-assisted processing of metallic materials. In this study, strain hardening in cold-rolled A6061 was effectively relieved using high-density pulsed electric current. By conducting comparative experiments under [...] Read more.

Understanding the respective roles of thermal and athermal effects during electric current treatment is critical for advancing current-assisted processing of metallic materials. In this study, strain hardening in cold-rolled A6061 was effectively relieved using high-density pulsed electric current. By conducting comparative experiments under room-temperature and liquid-nitrogen conditions, the thermal and athermal contributions were quantitatively evaluated. The results indicate that thermal effects dominate over athermal effects in dislocation density reduction and strain-hardening relief. Nevertheless, the athermal effect, driven by electron wind force, is capable of promoting dislocation motion and annihilation. This work provides a practical framework for evaluating thermal and athermal contributions and offers new insights into microstructure control via electric current, with implications for the design of advanced structural materials. Full article

(This article belongs to the Special Issue Integrated Forming, Treatment and Modelling of Lightweight Alloys)

► Show Figures

Figure 1

14 pages, 5655 KB

Open AccessArticle

Nitinol 3D Printed by Micro Gas Metal Arc-Based Direct Energy Deposition

by Paulo Henrique Grossi Dornelas, Tadeu Castro Silva, João Pedro Oliveira, Ana S. Ramos, Maria Reis and Telmo G. Santos

J. Manuf. Mater. Process. 2026, 10(6), 188; https://doi.org/10.3390/jmmp10060188 - 29 May 2026

Viewed by 537

Abstract

Additive manufacturing of NiTi shape memory alloys is challenging due to their sensitivity to composition and thermal history. The gap between high-resolution powder-based AM and high-productivity wire-based processes for NiTi remains a challenge. This study investigates the technical feasibility of depositing Ni-rich NiTi [...] Read more.

Additive manufacturing of NiTi shape memory alloys is challenging due to their sensitivity to composition and thermal history. The gap between high-resolution powder-based AM and high-productivity wire-based processes for NiTi remains a challenge. This study investigates the technical feasibility of depositing Ni-rich NiTi (56 wt.% Ni) using a micro gas metal arc-based directed energy deposition (µ-GMA-DED) process with a 300 µm wire. The investigation was conducted on a single-bead, single-layer geometry deposited onto a titanium substrate. The deposited layer exhibited a heterogeneous microstructure with dendritic and eutectic-like regions, where phase analysis revealed a mixture of NiTi and Ni₃Ti intermetallics. Differential scanning calorimetry showed suppression of the martensitic transformation in the as-deposited condition, likely due to the high fraction of non-transformable Ni₃Ti, compositional redistribution during rapid solidification, and potential substrate dilution. The nanoindentation results reflected this heterogeneity, with Young’s modulus ranging from 64 to 151 GPa. While post-deposition heat treatment partially restored the martensitic transformation, these results demonstrate the preliminary feasibility of the µ-GMA-DED process, noting that strict control over chemistry and dilution is required before the route can be applied to functional components. Full article

► Show Figures

Figure 1

29 pages, 18319 KB

Open AccessArticle

Effect of Porosity and Post-Processing on the Mechanical Performance of Additively Manufactured PEEK Osteoconductive Scaffolds

by Samreen Dallal, Babak Eslami and Saeed Tiari

J. Manuf. Mater. Process. 2026, 10(6), 187; https://doi.org/10.3390/jmmp10060187 - 29 May 2026

Viewed by 551

Abstract

Additive manufacturing enables the fabrication of porous polyetheretherketone (PEEK) structures with controlled architectures for biomedical applications. In particular, porous PEEK scaffolds have attracted significant attention due to their potential to enhance osteoconductivity while maintaining mechanical compatibility with bone. However, the relationship between porosity, [...] Read more.

Additive manufacturing enables the fabrication of porous polyetheretherketone (PEEK) structures with controlled architectures for biomedical applications. In particular, porous PEEK scaffolds have attracted significant attention due to their potential to enhance osteoconductivity while maintaining mechanical compatibility with bone. However, the relationship between porosity, post-processing conditions, and mechanical performance remains insufficiently understood, especially at high porosity levels. In this study, the effects of porosity (49–81%) and post-processing heat treatment (4 and 6 h at 300 °C) on the mechanical performance of additively manufactured PEEK osteoconductive scaffolds were experimentally investigated. Compression and three-point bending tests were conducted to evaluate strength and elastic modulus. Results demonstrated a strong inverse relationship between porosity and mechanical properties, with significant reductions observed beyond critical thresholds of approximately 66% in compression and 59% in bending. Heat treatment improved mechanical performance at lower porosity levels, likely due to enhanced crystallinity and interlayer bonding, while its effect diminished at higher porosities due to reduced load-bearing material and ligament thinning. These findings highlight the importance of optimizing porosity and post-processing conditions to achieve a balance between mechanical integrity and osteoconductive potential in PEEK scaffolds. The results provide practical design guidelines for the development of additively manufactured PEEK structures for load-bearing orthopedic applications. Full article

(This article belongs to the Special Issue Processing, Mechanical Properties, and Manufacturing Techniques of Advanced Composite Materials)

► Show Figures

Figure 1

16 pages, 13233 KB

Open AccessArticle

Influence of Zr Addition on the Phase Composition, Mechanical Properties, Deformation Behavior and Crystallographic Texture of the Al−Gd−Cr−Ti Alloy for Thermal Neutron Absorption

by S. M. Amer, A. El-Khouly, Dmitry Nikolayev, T. A. Lychagina, Amr. B. ElDeeb, L. E. Gorlov, O. A. Yakovtseva, R. Yu. Barkov, M. V. Glavatskikh and A. V. Pozdniakov

J. Manuf. Mater. Process. 2026, 10(6), 186; https://doi.org/10.3390/jmmp10060186 - 28 May 2026

Viewed by 586

Abstract

In the present study, a distinct core–shell structure comprising an Al₂₁GdCrTi core and an Al₃(Gd,Zr) shell was produced in the Al-7.9Gd-0.6Zr-0.2Cr-0.2Ti alloy after homogenization at 615 °C for 1 h. Concurrently, L1₂ nanoprecipitates (Al₃(Gd,Zr)) of 20–25 [...] Read more.

In the present study, a distinct core–shell structure comprising an Al₂₁GdCrTi core and an Al₃(Gd,Zr) shell was produced in the Al-7.9Gd-0.6Zr-0.2Cr-0.2Ti alloy after homogenization at 615 °C for 1 h. Concurrently, L1₂ nanoprecipitates (Al₃(Gd,Zr)) of 20–25 nm in size were formed. The neutron absorption reduction factor was evaluated at the Dubna research reactor, where a 1 mm thick rolled layer reduced the intensity of neutrons scattered from pure aluminum by a factor of 17 to 36. Cold rolling enhanced yield strength (175 ± 6 MPa) compared to hot–cold rolling (164 ± 2 MPa) but reduced elongation (11.9 ± 1.1% vs. 13.5 ± 0.2%), while ultimate tensile strength remained similar at 203 MPa. Full article

► Show Figures

Figure 1

15 pages, 12489 KB

Open AccessArticle

Influence of Hot-Pressing Temperature on the Microstructure and Mechanical Properties of LPBF-Manufactured Al-10Sn-10Pb Alloy

by K. O. Akimov, A. L. Skorentsev, N. M. Rusin, V. E. Liharev, A. Yu. Nikonov, D. P. Il’yashchenko and A. I. Dmitriev

J. Manuf. Mater. Process. 2026, 10(6), 185; https://doi.org/10.3390/jmmp10060185 - 28 May 2026

Viewed by 463

Abstract

Laser powder bed fusion (LPBF) of aluminum matrix tribological composites holds high potential for advanced bearing applications, yet its widespread implementation is often constrained by high porosity and severe residual stresses. In this work, the influence of hot pressing (HP) temperature (100–400 °C) [...] Read more.

Laser powder bed fusion (LPBF) of aluminum matrix tribological composites holds high potential for advanced bearing applications, yet its widespread implementation is often constrained by high porosity and severe residual stresses. In this work, the influence of hot pressing (HP) temperature (100–400 °C) on the microstructure, substructural evolution, mechanical properties, and fracture mechanisms of the LPBF Al-10Sn-10Pb alloy was investigated to achieve simultaneous densification and matrix optimization. Processing was carried out at 300 MPa with a 30 min holding time. It was established that at temperatures >200 °C, near-full consolidation is achieved through liquid-assisted pore closure. Increasing the temperature leads to the coarsening of Sn and Pb inclusions and the disruption of the initial dispersed network of soft phases. Williamson–Hall analysis revealed a transition from dislocation accumulation at 100 °C (~15 × 10¹³ m⁻²) to dynamic recovery at 200 °C, followed by matrix recrystallization at higher temperatures. A combination of strength (up to 127 MPa) and ductility (~11%) is realized at 200 °C due to the synergy between remaining substructural strengthening and pore healing. At 300–400 °C, the strength decreases to 108–113 MPa with a concomitant increase in ductility to 34–44%. A shift in fracture mechanisms from quasi-brittle to ductile is shown; at 400 °C, the development of intergranular fracture associated with the influence of liquid phases is possible. Full article

(This article belongs to the Special Issue Microstructure Control and Mechanical Behavior in Additively Manufactured Metallic Components)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

J. Manuf. Mater. Process., Volume 10, Issue 6 (June 2026) – 33 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI