Materials

12 pages, 5336 KB

Open AccessArticle

Study on Strengthening Mechanism of Arc Welding Interface Between TiC Steel-Bonded Carbides and Welding Material Based on First Principles

by Wei Wei, Shaokang Guan, Zhiquan Huang, Shuhao Zhu and Haiyan Zhang

Materials 2026, 19(13), 2901; https://doi.org/10.3390/ma19132901 (registering DOI) - 6 Jul 2026

Abstract

In this study, the effects of W, Cr, and Mo alloying elements on the microstructure and mechanical properties of the arc welding interface between TiC steel-bonded carbide and welding material were investigated using TEM, SEM, microhardness testing, and mechanical property testing. First-principles calculations [...] Read more.

In this study, the effects of W, Cr, and Mo alloying elements on the microstructure and mechanical properties of the arc welding interface between TiC steel-bonded carbide and welding material were investigated using TEM, SEM, microhardness testing, and mechanical property testing. First-principles calculations were employed for verification. The results indicate that, under the experimental conditions, the shear strength of the arc welding interface between the ZDZC60 carbide and the multi-component composite welding material (enhanced with W, Cr, and Mo) was 83% higher than that before optimization. The order of the three metal atoms when substituting Ti atoms in TiC particles was determined as W > Mo > Cr. The “core–rim” structure of TiC particles in the partially melted zone (PMZ) of the arc welding interface was proposed. The coherent structure of TiC particles, characterized by (200)TiC//(200)TiMoC₂//(200)TiWC₂ and [011]TiC//[011]TiMoC2//[011]TiWC2, was identified. W and Mo atoms exert an inhibitory effect on the dissolution of TiC particles, while Cr atoms disperse in the binder phase in the form of carbides and solid solutions, thereby effectively strengthening the interface. Full article

(This article belongs to the Section Metals and Alloys)

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24 pages, 1825 KB

Open AccessArticle

Innovative Connection of Non-Load-Bearing Walls Using a Spatially Arranged Silica Glass Mesh

by Radosław Jasiński and Iwona Galman

Materials 2026, 19(13), 2900; https://doi.org/10.3390/ma19132900 (registering DOI) - 6 Jul 2026

Abstract

Although non-structural walls do not determine the structural safety of a building, they are responsible for its functionality by serving as acoustic, thermal, and fire-resistant partitions. They may be freely located and relocated and are typically constructed during the finishing stage of building [...] Read more.

Although non-structural walls do not determine the structural safety of a building, they are responsible for its functionality by serving as acoustic, thermal, and fire-resistant partitions. They may be freely located and relocated and are typically constructed during the finishing stage of building works. Reliable performance of non-structural walls depends on appropriate connections to floors and adjacent walls. Connections to walls are most commonly achieved using traditional masonry bonding or sufficiently durable wall connectors, usually made of steel. An alternative to steel connectors may be connectors made of polymer-based materials or meshes. This paper proposes an innovative method for connecting non-structural masonry walls using a spatially arranged mesh, which serves not only as reinforcement of the wall connection but also as reinforcement of the bed joints. The aim of the study was to evaluate the effectiveness of this method in comparison with other connection techniques, including traditional solutions. Experimental investigations were carried out using an original test setup on 12 specimens made of AAC masonry units, divided into three series: series P—traditional connection (reference series), series H—connection with mesh placed in bed joints, and series SHP—connection with spatially arranged mesh. Silica Glass Mesh (SGM), intended for reinforcement of bed joints in AAC masonry, was used in the study. The experiments focused on the analysis of connection behavior and load-bearing capacity, with particular emphasis on maximum load values and failure mechanisms. Individual stages of the behavior of mesh-reinforced connections were identified, and empirical relationships enabling estimation of maximum loads were developed. The results confirmed that the traditional connection achieved the highest load-bearing capacity. However, as expected, the mesh-reinforced connections—particularly those with the spatial mesh arrangement—exhibited a more stable response and a greater ability for progressive load transfer. The SHP series connections with spatially arranged meshes exhibited significantly lower load-bearing capacity compared to the reference unreinforced connections, while at the same time demonstrating substantially greater deformability. The stiffness degradation in the mesh-reinforced connections did not occur abruptly, as observed in the reference models, which makes them an effective alternative for practical applications. Technical models for predicting forces and displacements of connections reinforced with spatially arranged meshes and meshes placed in bed joints were also developed. Full article

(This article belongs to the Special Issue Emerging Lightweight Metallic and Non-Metallic Materials: From Properties to Applications)

14 pages, 4710 KB

Open AccessArticle

Microstructure-Dependent Corrosion Behavior of Ferritic–Martensitic 17Cr Stainless Steel in CO₂-Saturated Brine at 230 °C Under High Pressure

by Song He, Zhile Yang, Xuesong Xing, Weiru Zheng, Xijin Xing and Xiaoqi Yue

Materials 2026, 19(13), 2899; https://doi.org/10.3390/ma19132899 (registering DOI) - 6 Jul 2026

Abstract

The corrosion behavior of ferritic–martensitic 17Cr stainless steel in CO₂-saturated brine was investigated using static autoclave immersion tests in 4.12 wt% NaCl solution at 230 °C under CO₂ partial pressures of 6.36, 18.28, and 24.57 MPa. The calculated in situ [...] Read more.

The corrosion behavior of ferritic–martensitic 17Cr stainless steel in CO₂-saturated brine was investigated using static autoclave immersion tests in 4.12 wt% NaCl solution at 230 °C under CO₂ partial pressures of 6.36, 18.28, and 24.57 MPa. The calculated in situ pH values obtained using the OLI System were 3.79, 3.55, and 3.49, respectively. Corrosion morphology, microstructural evolution, and corrosion products were characterized by SEM, EDS, EBSD, and Raman spectroscopy. The average mass-loss corrosion rate increased from 0.138 ± 0.0221 mm/year at 6.36 MPa pCO₂ to 0.326 ± 0.0142 mm/year at 24.57 MPa pCO₂. Although the specimens did not show severe macroscopic pitting, localized attack preferentially occurred in fine-grained martensitic banded regions. EBSD analysis revealed that these regions exhibited higher local misorientation and defect density, which may reduce the stability of Cr-rich surface films. Raman spectra identified Cr(OH)₃ in the corrosion products, and the Cr(OH)₃ signal became more evident with increasing CO₂ partial pressure. The results indicate that, under fixed temperature and salinity, the corrosion behavior of 17Cr stainless steel is governed by CO₂ partial pressure and microstructural heterogeneity. Full article

(This article belongs to the Section Corrosion)

23 pages, 6645 KB

Open AccessArticle

Effect of Propylene Glycol Coolant pH on the Galvanic Corrosion Behavior of 6061 Aluminum Alloy/304 Stainless Steel

by Hao Miao, Cong Shao, Jinqiao Zheng, Hao Yu, Heqian Wang and Kui Xiao

Materials 2026, 19(13), 2898; https://doi.org/10.3390/ma19132898 (registering DOI) - 6 Jul 2026

Abstract

6061 aluminum alloy is lightweight and has good thermal conductivity, while 304 stainless steel possesses excellent mechanical properties and corrosion resistance; both have broad application prospects in cooling circuits. Propylene glycol coolant shows great potential in liquid cooling systems due to its low [...] Read more.

6061 aluminum alloy is lightweight and has good thermal conductivity, while 304 stainless steel possesses excellent mechanical properties and corrosion resistance; both have broad application prospects in cooling circuits. Propylene glycol coolant shows great potential in liquid cooling systems due to its low toxicity and good antifreeze properties. However, during operation, galvanic corrosion may occur when the two metals come into direct contact within the coolant, thereby threatening system safety and service life. This study focuses on 6061 aluminum alloy, 304 stainless steel, and their galvanic couples. Electrochemical testing, SEM, 3D confocal microscopy, and XPS were used to systematically investigate their self-corrosion and galvanic corrosion behavior in propylene glycol coolant at pH values of 4.8, 6.8, and 8.8. The results indicate that 6061 aluminum alloy is more sensitive to pH changes; its corrosion resistance first increases and then decreases as pH rises, with the least corrosion occurring at pH = 6.8 and the most severe at pH = 4.8. 304 stainless steel exhibited lower corrosion rates at pH 6.8 and 8.8, but corrosion significantly worsened at pH 4.8. For the 6061 aluminum alloy/304 stainless steel couple, the galvanic current first decreased and then increased with rising pH, while the galvanic potential first increased and then decreased. The 6061 aluminum alloy consistently acted as the anode, and the 304 stainless steel consistently acted as the cathode, with the highest sensitivity to galvanic corrosion observed at pH 4.8. XPS analysis shows that under different pH conditions, the corrosion products of 6061 aluminum alloy are Al(OH)₃ and Al₂O₃, while the main components of the passivation film on 304 stainless steel remain unchanged. Full article

(This article belongs to the Special Issue Advances in Lightweight Alloys: Microstructure, Mechanical Properties and Applications)

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18 pages, 1968 KB

Open AccessArticle

Ultrasonic Soldering of AlN/Cu Using SiC-Modified Zn5Al3Ti Active Solder

by Tomas Melus, Roman Kolenak, Mikulas Sloboda, Peter Gogola and Matej Pasak

Materials 2026, 19(13), 2897; https://doi.org/10.3390/ma19132897 (registering DOI) - 6 Jul 2026

Abstract

This study investigates the effect of SiC nanoparticle addition on the microstructure, interfacial reactions, and mechanical properties of Zn5Al3Ti active solder used for ultrasonic soldering of AlN ceramic to copper substrates. Composite solders containing 3 and 6 wt.% SiC nanoparticles were prepared and [...] Read more.

This study investigates the effect of SiC nanoparticle addition on the microstructure, interfacial reactions, and mechanical properties of Zn5Al3Ti active solder used for ultrasonic soldering of AlN ceramic to copper substrates. Composite solders containing 3 and 6 wt.% SiC nanoparticles were prepared and applied under flux-free ultrasonic soldering conditions. The solder alloys were evaluated by tensile testing, while the soldered joints were evaluated by shear strength testing. The solder microstructure and interfacial regions were characterized using SEM/EDS analysis. The results showed that the addition of SiC nanoparticles modified the microstructure of the Zn5Al3Ti solder and influenced the mechanical performance of the ceramic/metal joints. Among the investigated systems, the AlN/Zn5Al3Ti + 6 wt.% SiC/Cu joint exhibited the highest shear strength, reaching approximately 101 MPa. SEM/EDS observations revealed the formation of compact multilayered interfacial regions, including possible Cu–Zn intermetallic phases at the Cu/solder interface and Al–Ti–Zn-based reaction products near the solder/AlN interface. The improved joint performance may be attributed to the combined effect of SiC-induced microstructural modification, the presence of Si-containing particles, and the formation of compact metallurgical bonds. The results indicate that Zn5Al3Ti solder modified with 6 wt.% SiC nanoparticles is a promising material for producing strong AlN/Cu joints under the applied ultrasonic soldering conditions. Full article

(This article belongs to the Special Issue Mechanical and Metallurgical Behaviour of Welded Materials—2nd Edition)

37 pages, 14097 KB

Open AccessReview

An Overview and Perspectives on the Materials Genome Initiative-Based Asphalt Mix Design Framework

by Jian Liu, Zhen Wang, Fanijo Ebenezer and Linbing Wang

Materials 2026, 19(13), 2896; https://doi.org/10.3390/ma19132896 - 6 Jul 2026

Abstract

Traditional asphalt mix design approaches are trial-and-error processes and are limited in their ability to find high-performance asphalt mixtures to ensure long-term highway durability. The Materials Genome Initiative (MGI) launched in 2011 is designed to accelerate the development of advanced materials by integrating [...] Read more.

Traditional asphalt mix design approaches are trial-and-error processes and are limited in their ability to find high-performance asphalt mixtures to ensure long-term highway durability. The Materials Genome Initiative (MGI) launched in 2011 is designed to accelerate the development of advanced materials by integrating experiments, computational modeling, and big data analytics and has achieved remarkable progress in other materials design, which demonstrates strong potential for applying the MGI framework to optimize asphalt mix design. This study systematically reviews the application prospects of MGI methodologies in asphalt mixture design. Specifically, it first reviews recent progress in MGI for materials design and summarizes current research efforts to optimize asphalt mix design using traditional laboratory testing, numerical simulations (e.g., finite element method and discrete element method), and artificial intelligence while identifying their respective limitations. To overcome the limitations of each pillar, it is necessary to integrate these individual modules into a comprehensive MGI-based asphalt mix design framework. Furthermore, this study reviews the research on advanced experimental techniques for the multiscale characterization of asphalt binders and aggregates and defines the asphalt mixture genome, including binder-related genes, aggregate-related genes, and compaction-related genes. Finally, the specific steps for developing an MGI-based asphalt mix design framework are elaborated. Full article

(This article belongs to the Section Construction and Building Materials)

32 pages, 27101 KB

Open AccessReview

MXene-Based Photocatalysts for Pharmaceutical Wastewater Remediation and Sustainable Energy Conversion: Mechanisms, Interface Engineering, and Future Perspectives

by Zhizhen Feng, Shanshan Han, Hong Yan, Jiaqi Shi, Yuxin Ma, Tongtong Wang, Xingchang Zhang and Junchao Jia

Materials 2026, 19(13), 2895; https://doi.org/10.3390/ma19132895 (registering DOI) - 6 Jul 2026

Abstract

Pharmaceutical residues in wastewater pose persistent ecological and public health risks, creating an urgent need for efficient and sustainable remediation technologies. MXene-based photocatalysts have attracted growing interest owing to their high electrical conductivity, tunable surface chemistry, abundant active sites, and excellent charge-transfer capability. [...] Read more.

Pharmaceutical residues in wastewater pose persistent ecological and public health risks, creating an urgent need for efficient and sustainable remediation technologies. MXene-based photocatalysts have attracted growing interest owing to their high electrical conductivity, tunable surface chemistry, abundant active sites, and excellent charge-transfer capability. This review summarizes recent advances in MXene-based photocatalytic systems for pharmaceutical wastewater treatment and renewable energy production. Key topics include pharmaceutical degradation pathways, reactive oxygen species generation, ecotoxicological implications, and the multifunctional roles of MXenes as conductive supports, electron mediators, and cocatalysts. Interfacial engineering strategies, including Z-scheme, S-scheme, and Schottky heterojunctions, are discussed with respect to light absorption, charge separation, and interfacial redox reactions. Practical considerations, such as reactor design, life cycle assessment, and techno-economic feasibility, are also addressed. Finally, current challenges and future directions are highlighted, particularly scalable fluorine-free synthesis, improved oxidative stability, and machine learning-assisted material design. This review provides a concise framework for developing stable, efficient, and scalable MXene-based photocatalytic platforms for pharmaceutical wastewater remediation and sustainable energy generation. Full article

(This article belongs to the Section Green Materials)

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14 pages, 4840 KB

Open AccessArticle

Flow Stress Model of Hot Deformation for CoNiV Medium Entropy Alloy

by Qixuan Hao, Biao Zhang, Yuntian Du, Yaliang Liu, Minghe Zhang and Yunli Feng

Materials 2026, 19(13), 2894; https://doi.org/10.3390/ma19132894 - 6 Jul 2026

Abstract

Hot compression experiments were performed to characterize the high-temperature deformation behavior of CoNiV medium-entropy alloy (MEA). Hot compression tests were carried out using a Gleeble-3500 thermomechanical simulator over strain rates of 0.001 s⁻¹ to 1 s⁻¹ and temperatures ranging between 950 [...] Read more.

Hot compression experiments were performed to characterize the high-temperature deformation behavior of CoNiV medium-entropy alloy (MEA). Hot compression tests were carried out using a Gleeble-3500 thermomechanical simulator over strain rates of 0.001 s⁻¹ to 1 s⁻¹ and temperatures ranging between 950 °C and 1100 °C. Based on the experimentally determined hot compression data, three models for predicting the flow stress of CoNiV MEA were established: the Zerilli-Armstrong (Z-A) constitutive model, an artificial neural network (ANN) model, and a gated recurrent unit (GRU) model. This study comprehensively evaluated the prediction accuracy of each model using the coefficient of determination (R²), mean absolute error (MAE), and root mean square error (RMSE). The results show that, compared with the other two models, the Z-A model cannot accurately predict the flow behavior of CoNiV MEA in the studied hot-working regime. The R² value of the ANN model is 0.98974, while the GRU model exhibits the highest predictive capability, with an R² value of 0.98981, an MAE of 6.29621, and an RMSE of 13.10832. The proposed model demonstrates superior prediction accuracy compared with other models, enabling high-precision characterization of the high-temperature evolution of the flow stress in the CoNiV MEA. This study provides a theoretical foundation for the design and optimization of hot working parameters for the CoNiV MEA. Full article

(This article belongs to the Section Metals and Alloys)

17 pages, 5950 KB

Open AccessArticle

Effects of Zinc Diethyldithiocarbamate (ZDC) on Rheological Behavior and Aging Resistance of SBS-Modified Asphalt

by Zhenshi Zhong, Shi Xu, Shichao Liang, Xiongjiang Wang, Yongping Hu, Georgios Pipintakos, Shisong Ren, Quantao Liu and Shaopeng Wu

Materials 2026, 19(13), 2893; https://doi.org/10.3390/ma19132893 - 6 Jul 2026

Abstract

Aging of Styrene–butadiene–styrene (SBS)-modified asphalt accelerates the degradation of both the SBS polymer network and asphalt components, resulting in deterioration of the durability of asphalt concrete. This study investigates the use of zinc diethyldithiocarbamate (ZDC), a multifunctional antioxidant, in SBS-modified asphalt to improve [...] Read more.

Aging of Styrene–butadiene–styrene (SBS)-modified asphalt accelerates the degradation of both the SBS polymer network and asphalt components, resulting in deterioration of the durability of asphalt concrete. This study investigates the use of zinc diethyldithiocarbamate (ZDC), a multifunctional antioxidant, in SBS-modified asphalt to improve its aging resistance. Physical property tests, dynamic rheological analysis, multiple stress creep recovery (MSCR) and Fourier transform infrared spectroscopy (FTIR) assays were conducted to evaluate the rheological and chemical properties of asphalt binders before and after thermo-oxidative and UV aging. The results indicate that the incorporation of ZDC improved the deformation resistance and elastic recovery of SBS-modified asphalt. After aging, the ZDC/SBS composite-modified asphalt exhibited lower performance change rate than conventional SBS-modified asphalt, indicating enhanced resistance to permanent deformation and aging-induced damage. FTIR analysis demonstrated that ZDC effectively inhibited the formation of oxygen-containing functional groups during aging, suggesting suppressed oxidative reactions within the asphalt binder. The 5% ZDC dosage reduces the carbonyl index of SBS-modified asphalt by 36.48% after thermo-oxidative aging, and by 21.89% after UV aging, showing a stronger chemical inhibition effect on thermo-oxidative reactions. From the perspective of rheological performance stability, ZDC lowers the variation amplitude of non-recoverable creep compliance by 35.32% before and after thermo-oxidative aging and 41.46% before and after UV aging, and delivers a more prominent mitigating effect on property fluctuations triggered by UV aging. This indicates that ZDC exerts differentiated anti-aging mechanisms on thermo-oxidative and UV aging, with considerable potential to improve the comprehensive aging resistance of polymer-modified asphalt binders. Full article

(This article belongs to the Special Issue Material Characterization, Design and Modeling of Asphalt Pavements)

26 pages, 1711 KB

Open AccessArticle

A Meso-Scale Computational Framework for Predicting Fracture Mechanisms in 3D-Printed Bouligand Cementitious Metamaterials

by Xuelian Yuan, Yaqing Jiang and Huiting Xiong

Materials 2026, 19(13), 2892; https://doi.org/10.3390/ma19132892 - 6 Jul 2026

Abstract

The inherent brittleness of cementitious materials presents a fundamental limitation for advanced structural applications. While bio-inspired Bouligand architectures have demonstrated remarkable damage tolerance in natural composites, their systematic translation to brittle inorganic binders via 3D concrete printing (3DCP)—and the development of high-fidelity meso-scale [...] Read more.

The inherent brittleness of cementitious materials presents a fundamental limitation for advanced structural applications. While bio-inspired Bouligand architectures have demonstrated remarkable damage tolerance in natural composites, their systematic translation to brittle inorganic binders via 3D concrete printing (3DCP)—and the development of high-fidelity meso-scale models to quantitatively map the resulting strength–toughness design space—remains underexplored. This study aims to decouple the intrinsic topological toughening potential of helicoidal Bouligand architectures from the stochastic defects inherent to additive manufacturing, through a meso-scale finite element (FE) framework. To physically validate the model, a nano-clay-assisted rheological strategy was utilized to enable the support-free fabrication of these helicoidal prototypes. Computationally, a meso-scale FE framework integrating the concrete damaged plasticity (CDP) model with three-dimensional cohesive zone elements was developed to explicitly resolve inter- and intra-layer interfacial crack kinematics. Coupled physical compression tests and numerical simulations indicate that the 15° Bouligand architecture achieves a computationally predicted 16.3-fold increase in volumetric energy absorption (experimentally: 13.7-fold) compared to the 0° unidirectional baseline, with a modest ~11% reduction in compressive strength (from ~33.0 MPa to ~29.5 MPa in simulations; ~12% experimentally). Furthermore, numerical parametric studies across the complete pitch-angle design space reveal an optimal topological window at 15–30°, wherein the competing effects of crack deflection and structural integrity are balanced. Imperfection sensitivity analysis demonstrates that the topological toughening mechanism is relatively robust: even with a 30% reduction in inter-filament bonding strength, the work of fracture remains 12.4 times higher than that of the 0° control. These findings suggest that spatial toolpath programming offers a viable, geometry-driven strategy for developing damage-tolerant cementitious composites, complementing conventional material-level reinforcement approaches. Full article

(This article belongs to the Section Construction and Building Materials)

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16 pages, 7573 KB

Open AccessArticle

Effects of Cellulose Nanofiber Reinforcement on the Properties of Three-Dimensional-Printed Denture Base Resin: An In Vitro Study

by Xiangyu Ren, Tamaki Hada, Keyu Qi, Masanao Inokoshi, Motohiro Uo and Manabu Kanazawa

Materials 2026, 19(13), 2891; https://doi.org/10.3390/ma19132891 - 6 Jul 2026

Abstract

Although the use of three-dimensional-printed (3D-printed) denture base resins is becoming increasingly widespread in digital dentistry, information regarding the reinforcing effects of cellulose nanofibers and their most favorable concentration remains limited. We evaluated the effects of adding cellulose nanofibers (CNFs, 0–2.0 wt%) on [...] Read more.

Although the use of three-dimensional-printed (3D-printed) denture base resins is becoming increasingly widespread in digital dentistry, information regarding the reinforcing effects of cellulose nanofibers and their most favorable concentration remains limited. We evaluated the effects of adding cellulose nanofibers (CNFs, 0–2.0 wt%) on the mechanical and physical properties of three-dimensional-printed denture base resins. The addition of cellulose nanofibers improved flexural strength (FS) and Vickers hardness (HV), with more balanced performance observed at low concentrations; no significant differences were observed in flexural modulus. Color stability did not show a linear concentration-dependent trend, and the 1.0 wt% group exhibited the most favorable overall performance. Water sorption slightly increased at higher CNF concentrations. SEM observations revealed relatively uniform CNF dispersion at lower concentrations, whereas agglomeration and void formation occurred at higher concentrations. Appropriate CNF incorporation may be a promising strategy for reinforcing 3D-printed denture base materials. Full article

(This article belongs to the Special Issue High Performance 3D Printing Materials)

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32 pages, 860 KB

Open AccessReview

Using Magnesium and Magnesium-Based Alloys as a Novel Biomaterial to Create Medical Devices by AM Techniques—A Review

by Corneliu Munteanu, Ioana-Ilinca Volocaru, Boris Nazar, Fabian-Cezar Lupu, Bogdan Oprisan, Ioana-Alexandra Stan, Grigorii Deleu and Gabriela Stan

Materials 2026, 19(13), 2890; https://doi.org/10.3390/ma19132890 - 6 Jul 2026

Abstract

Magnesium alloys are considered to be the third generation of biomaterials used in biomedical applications to promote bone tissue regeneration. Due to their Young’s modulus being similar to that of human bone and their release of magnesium ions that are antimicrobial and osteoinductive, [...] Read more.

Magnesium alloys are considered to be the third generation of biomaterials used in biomedical applications to promote bone tissue regeneration. Due to their Young’s modulus being similar to that of human bone and their release of magnesium ions that are antimicrobial and osteoinductive, these biomaterials not only promote bone regeneration, minimize the effects of stress shielding and reduce the risk of infection, but also their exceptional biocompatibility and bioresorbability eliminate the need for a second surgery to remove the implant. However, because magnesium has poor corrosion resistance, without different coatings and surface treatments, the implant can be compromised before the bone is fully healed. With additive manufacturing (AM) as a revolutionary technology, the one-size-fits-all approach can be replaced by fully personalized medicine, in which complex shapes can be created, designed, and processed with unique parameters for each patient. However, 3D printing of Mg-based devices remains particularly challenging due to magnesium’s high chemical reactivity, combustion risk, and low vaporization temperature, challenges that are further compounded when alloying elements are introduced. This review addresses this gap by critically examining the properties, corrosion behavior, and bio-medical performance of Mg and its alloys, with a focused analysis of selective laser melting (SLM) and wire arc additive manufacturing (WAAM) as key fabrication methods. The influence of processing parameters, microstructural defects, and alloy composition on the final properties of AM-fabricated Mg components is systematically discussed, alongside current limitations and prospective strategies toward their clinical translation. Full article

(This article belongs to the Special Issue Additive Manufacturing of Metals and Alloys: Microstructure and Mechanical Properties—Second Edition)

19 pages, 2523 KB

Open AccessArticle

Low-Temperature Magnetotransport of Mixed Polycrystalline Rutile, Anatase and Brookite Phases of TiO₂

by Josipa Šćurla, Trpimir Ivšić, Gaurav Pransu, Nikola Jakupec, Neven Barišić, László Forró and Ante Bilušić

Materials 2026, 19(13), 2889; https://doi.org/10.3390/ma19132889 - 6 Jul 2026

Abstract

The anatase and rutile phases of titanium dioxide (TiO₂) have been widely studied for their photocatalytic and electronic properties, while the brookite phase is rarely explored. The investigations of intrinsic magnetotransport in mixed-phase systems are limited. Magnetic susceptibility and magnetotransport measurements [...] Read more.

The anatase and rutile phases of titanium dioxide (TiO₂) have been widely studied for their photocatalytic and electronic properties, while the brookite phase is rarely explored. The investigations of intrinsic magnetotransport in mixed-phase systems are limited. Magnetic susceptibility and magnetotransport measurements were performed between 2 K and 300 K in magnetic fields up to 12 T. Both samples with different anatase–rutile–brookite ratios exhibit Curie–Weiss susceptibility. Transport measurements reveal an insulating behavior at low temperatures with activation energies 1–20 meV and signatures of variable-range hopping (VRH) conduction. Strong positive magnetoresistance at low temperatures obeys the Efros–Shklovskii VRH model. Full article

(This article belongs to the Section Materials Physics)

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23 pages, 14851 KB

Open AccessArticle

Characterization of Powder Bed Fusion–Laser Beam Ti6Al4V Samples in the As-Built and Stress-Relief States

by Paola Leo, Gilda Renna, Andrea Amleto De Luca, Chiara Scaramuzzi, Neetesh Soni, Francesco Willem Panella, Teresa Primo and Gabriele Papadia

Materials 2026, 19(13), 2888; https://doi.org/10.3390/ma19132888 - 6 Jul 2026

Abstract

Despite the advantages of powder bed fusion–laser beam (PBF-LB), Ti6Al4V components often exhibit high yield strength but limited ductility, which restricts their use in critical structural applications. This study aims to identify the most effective heat treatment to optimize the strength–ductility balance in [...] Read more.

Despite the advantages of powder bed fusion–laser beam (PBF-LB), Ti6Al4V components often exhibit high yield strength but limited ductility, which restricts their use in critical structural applications. This study aims to identify the most effective heat treatment to optimize the strength–ductility balance in Ti6Al4V parts produced by PBF-LB and to establish direct correlations between microstructural states, mechanical properties and corrosion behavior. Two distinct post-processing heat treatments were applied, specifically, the first at 500 °C for 5 h and the second at 800 °C for 2 h, both followed by air cooling. The microstructure was characterized using optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Mechanical behavior was assessed through Vickers microhardness testing and tensile testing, while corrosion resistance was evaluated via electrochemical measurements. Residual stress profiles were determined using the hole-drilling strain gauge method, in both as-built and heat-treated conditions. The as-built samples displayed a fully martensitic α′ structure with columnar grains aligned parallel to the laser scanning direction, resulting from rapid solidification. Heat treatment at 500 °C caused only partial decomposition of acicular martensite into substructures without altering its acicular morphology, leading to a strengthening effect alongside a reduction in ductility. Conversely, heat treatment at 800 °C offered the most balanced combination of strength and ductility among the conditions studied, albeit with a moderate reduction in corrosion resistance. Full article

(This article belongs to the Special Issue Additive Manufacturing of Metallic Alloys and Composite Materials—Process, Structure, Properties and Part Performance: Experimental and Computer Methods)

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32 pages, 2597 KB

Open AccessReview

Advances in Materials for Strontium–Yttrium Separation: A Comprehensive Review

by Mali Xu, Zhimin Wang, Tong Zhang, Siqi Ma, Shengyang Zhao, Yonggang Zhao and Yan Chen

Materials 2026, 19(13), 2887; https://doi.org/10.3390/ma19132887 - 6 Jul 2026

Abstract

Yttrium-90 (⁹⁰Y) is a pivotal pure beta-emitting radionuclide extensively employed in the targeted therapy of malignant tumors, such as hepatocellular carcinoma and lymphoma. The ⁹⁰Sr-⁹⁰Y generator system represents the most effective method for producing no-carrier-added (NCA) ⁹⁰Y [...] Read more.

Yttrium-90 (⁹⁰Y) is a pivotal pure beta-emitting radionuclide extensively employed in the targeted therapy of malignant tumors, such as hepatocellular carcinoma and lymphoma. The ⁹⁰Sr-⁹⁰Y generator system represents the most effective method for producing no-carrier-added (NCA) ⁹⁰Y to meet escalating clinical demands. However, safe clinical application necessitates the stringent separation of its parent isotope, ⁹⁰Sr, which poses significant radiotoxicological risks due to its long half-life and bone-seeking behavior. This review comprehensively summarizes recent advances in solid-phase adsorbent materials developed for the high-efficiency separation of Y³⁺ and Sr²⁺. We systematically analyze the design strategies, molecular recognition mechanisms, and performance evaluation metrics of various functional systems. Key materials discussed include extraction chromatography (EXC) resins based on organophosphorus extractants, diglycolamide (DGA) derivatives, and crown ethers, as well as inorganic ion exchangers such as antimony-based materials, manganese oxides, and zeolite-like molecular sieves. Special attention is given to composite modification strategies, including silica-based and polymer-matrix composites, and metal doping techniques aimed at enhancing radiation resistance, acid stability, and Sr-Y separation factors (SF). Finally, we provide an outlook on the future development of next-generation ⁹⁰Sr-⁹⁰Y generator materials, highlighting the imperative of transitioning from idealized simulated environments to robust, field-ready applications. Full article

(This article belongs to the Section Advanced Composites)

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22 pages, 19259 KB

Open AccessArticle

Interfacial Characteristics of a Fly Ash-Based Artificial Aggregate

by Xiaoxing Zeng, Qijun Yu, Jiangxiong Wei, Fang Zhang and Qian Sun

Materials 2026, 19(13), 2886; https://doi.org/10.3390/ma19132886 - 6 Jul 2026

Abstract

A fly ash-based artificial aggregate with a compressive strength of >60 MPa was prepared via cement activation and alkali activation using >75% fly ash as the principal raw material. The mechanical properties of concrete prepared using this aggregate and the characteristics of the [...] Read more.

A fly ash-based artificial aggregate with a compressive strength of >60 MPa was prepared via cement activation and alkali activation using >75% fly ash as the principal raw material. The mechanical properties of concrete prepared using this aggregate and the characteristics of the interfacial transition zone (ITZ) were compared with those of concrete containing natural aggregate. The results indicated that the compressive strength of concrete prepared using artificial aggregate was lower than that of concrete prepared using natural aggregate by about 19.0–27.6%. Scanning electron microscopy (SEM) revealed that the cement paste bonded tightly to the surface of the natural aggregate; the width of ITZ was 20–30 µm. The ITZ between the cement paste and the fly ash-based artificial aggregate exhibited a relatively loose structure at 28 d, with a width of 30–40 µm; however, the ITZ became narrower and denser at 90 d. EDS indicated that the principal hydration products were calcite crystals and C-S-H gel in the ITZ of natural aggregate concrete and artificial aggregate concrete. According to nanoindentation tests, for both cement pastes with natural and artificial aggregates, the elastic modulus of the ITZ at 28 d was >10 GPa, and it increased slightly at 90 d. The ITZ between the alkali-activated paste and limestone exhibited a relatively dense structure, with a width of 20–30 µm. The ITZ between the alkali-activated paste and the fly ash-based artificial aggregate exhibited a relatively loose structure with numerous pores at 28 d and had a width of 30–40 µm; however, the ITZ became narrower and denser at 90 d. The principal hydration products were N-A-S-H and C-A-S-H in the two kinds of aggregate concrete. Whether the alkali-activated paste contained natural aggregate or artificial aggregate, the elastic modulus of the ITZ at 28 d was 5–6 GPa, and it increased rapidly to >10 GPa by 90 d. The performance of ITZ is primarily influenced by the matrix materials, while also being influenced by aggregates and curing conditions. Qualitative and quantitative analyses revealed the formation mechanisms of artificial and natural aggregates in different matrices. Through continuous hydration and polymerization reactions, artificial aggregates gradually form narrower and denser interfacial transition zones with different matrices, especially in alkali-activated matrices. The continuously improved performance of the ITZ makes it less prone to forming cracks between the ITZ and the artificial aggregate. This study provides an important theoretical basis for the application of fly ash-based artificial aggregates, which can also be used to produce high-strength concrete. Full article

(This article belongs to the Special Issue Advances in Alkali-Activated Materials (AAMs) and Their Applications)

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29 pages, 11991 KB

Open AccessArticle

Force–Thermal Coupling Effects on Surface Integrity and Subsurface Damage of Al-50 wt% Si Alloy During Milling

by Lu Jing, Fengjun Chen, Qiulin Niu, Qiu Hong, Jian Liu and Jiangnan Ding

Materials 2026, 19(13), 2885; https://doi.org/10.3390/ma19132885 - 6 Jul 2026

Abstract

Al-50 wt% Si alloy is widely used in aerospace and electronics but is hard to machine owing to uneven microstructure. To elucidate the relationship between force–thermal coupling effects and surface integrity during Al-50 wt% Si alloy milling, this paper established a stress model [...] Read more.

Al-50 wt% Si alloy is widely used in aerospace and electronics but is hard to machine owing to uneven microstructure. To elucidate the relationship between force–thermal coupling effects and surface integrity during Al-50 wt% Si alloy milling, this paper established a stress model to reveal the superposition mechanism of mechanical and thermal stresses. Experiments were conducted to investigate the evolution of cutting forces and temperatures, as well as their influence on surface integrity characteristics, including microhardness, roughness, and chip morphology. The results showed that temperature increases steadily with v_c, whereas cutting force fluctuates in an irregular manner. The maximum cutting temperature rises by 85.04% as v_c increases from 25 m/min to 125 m/min. Meanwhile, the thermo-mechanical coupling effect exerts a regulatory role on chip morphology, where higher v_c improves chip continuity and ductility. Surface integrity is determined by the competitive interplay between work hardening and thermal softening, and the surface microhardness varies from 168.49 HV to 173.27 HV. Specifically, elevated v_c optimizes surface quality, with the Ra decreasing by 24.54%, whereas excessive f_z and a_p aggravate damage. Ultimately, surface defects arise from the combined removal behavior of Si particles and deformation of the Al matrix, while the inhomogeneous stress field induces subsurface damage. Full article

(This article belongs to the Special Issue Advanced Materials Machining: Theory and Experiment)

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25 pages, 3250 KB

Open AccessArticle

Microwave-Assisted Production and Regeneration of Granular Expanded Graphite for the Adsorption of Cationic Dye Methylene Blue from Aqueous Solutions

by Alireza Faraji, Donatella Caniani, Delfina Bersano, Salvatore Masi, Ignazio M. Mancini, Linda Y. Tseng and Tanju Karanfil

Materials 2026, 19(13), 2884; https://doi.org/10.3390/ma19132884 - 6 Jul 2026

Abstract

This study investigated the use of microwave (MW) to enhance the performance of a granular thermo-plasma expanded graphite (GTPEG) to remove an organic cationic dye, methylene blue (MB), from freshwater, taking the benefits of MW-assisted regeneration. Expanded graphite (EG), low-density and mesoporous, has [...] Read more.

This study investigated the use of microwave (MW) to enhance the performance of a granular thermo-plasma expanded graphite (GTPEG) to remove an organic cationic dye, methylene blue (MB), from freshwater, taking the benefits of MW-assisted regeneration. Expanded graphite (EG), low-density and mesoporous, has been proposed previously as a means of extracting organic compounds from water due to its hydrophobicity and weak polarity. We granularized EG to facilitate its subsequent regeneration and reuse and separation, and MW was used to improve the adsorption of EG. The most important factors affecting adsorption were determined using response surface methodology, along with 3-D graphics illustrating the relationship between several variables. The experimental results show that 94% of MB adsorbed onto MW-GTPEG in deionized distilled water within 20 min. Additionally, adsorbent regeneration using MW did not affect the adsorption capacity and rate after 10 cycles albeit with a small weight loss of <8%. From our results, we believe that the main factor affecting the adsorption was the physical characteristics of the adsorbent, with other minor factors such as the adsorbent dose and initial concentration. Our findings suggest that MW irradiation may be a promising alternative for enhancing and regenerating GTPEG. Full article

(This article belongs to the Special Issue Advanced Adsorbent Materials: Preparation, Performance, Applications)

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12 pages, 3419 KB

Open AccessCommunication

A Numerical Study on Molten Pool Behavior and Ribbon Thickness Under Varying Casting Parameters in Planar Flow Casting

by Lijun Li, Jianliang Sun, Hongxin Ji, Deren Li, Baisong Li, Na Lv, Xianyan Wang and Xiangyu Lv

Materials 2026, 19(13), 2883; https://doi.org/10.3390/ma19132883 - 6 Jul 2026

Abstract

Despite the widespread use of planar flow casting (PFC) for amorphous alloy ribbons, previous two-dimensional (2D) numerical studies have primarily focused on isolated flow or thermal behaviors, lacking a systematic quantification of how key casting parameters collectively influence melt puddle geometry and ribbon [...] Read more.

Despite the widespread use of planar flow casting (PFC) for amorphous alloy ribbons, previous two-dimensional (2D) numerical studies have primarily focused on isolated flow or thermal behaviors, lacking a systematic quantification of how key casting parameters collectively influence melt puddle geometry and ribbon thickness. To fill this gap, this work establishes a coupled air–melt two-phase 2D Volume of Fluid (VOF) model based on the continuity, momentum, and energy equations. An analysis was conducted on how various parameters affect the melt puddle behavior and ribbon thickness. The results indicate that, as the roller speed (U) increases from 21 m/s to 30 m/s, the detachment length (Ln) decreases by 31%. Over the same interval, the puddle length (L) decreases by 30%. When the ejection speed (V) increases from 1.4 m/s to 2.0 m/s, the ejection temperature (

T_{e}

) increases from 1433 K to 1733 K, and the slit width (W) increases from 0.4 mm to 0.6 mm, Ln rises by roughly 39.7–133%, while L increases by approximately 32.3–112%. To produce thinner amorphous ribbons for loss reduction, high roller speed, low ejection speed, and small nozzle slit are crucial parameters. Full article

(This article belongs to the Section Metals and Alloys)

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