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13 pages, 292085 KB

Open AccessArticle

Tailoring the Microstructure of Ti-6Al-4V Alloy Fabricated by Hybrid Additive Manufacturing via Rolling Strategies

by Jixin Yang, Zhiqin Yang, Xu Gu, Ying Bao and Huaping Tang

Materials 2026, 19(18), 3812; https://doi.org/10.3390/ma19183812 - 8 Sep 2026

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Abstract

In situ rolling-assisted laser directed energy deposition (IR-LDED) was employed to fabricate Ti-6Al-4V titanium alloy samples, focusing on the microstructural characteristics under various rolling strategies. The results indicate that the microstructure was primarily governed by the interplay between temperature-dependent deformation and recrystallization processes. [...] Read more.

In situ rolling-assisted laser directed energy deposition (IR-LDED) was employed to fabricate Ti-6Al-4V titanium alloy samples, focusing on the microstructural characteristics under various rolling strategies. The results indicate that the microstructure was primarily governed by the interplay between temperature-dependent deformation and recrystallization processes. In situ rolling at elevated temperature, combined with complex thermal cycling, promoted recrystallization within the deposited material, leading to significant grain refinement. After remelting and high-temperature rolling, the average grain size in the middle region of the sample was refined to 21 μm, accompanied by high kernel average misorientation (KAM_avg) value of 1.92. Increasing the number of rolling passes at lower temperatures further reduced the grain size and decreased the KAM_avg. Following in situ rolling, the deposited material underwent remelting, and additional rolling at elevated temperatures increased both deformation and KAM_avg. The rearrangement of dislocations, formation of subgrain boundaries, and enhanced solute diffusion collectively facilitated the globularization of lamellar α phases, ultimately forming a microstructure composed of globular α, lamellar α/β, and dot-like β phases. Full article

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

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29 pages, 14184 KB

Open AccessArticle

Investigation of Microstructure, Hardness, and Wear Behavior of Hardfacing Produced by Wire Laser Additive Manufacturing

by Natan Damian Crozetta, Andeson Daleffe, Pedro Henrique Menegaro Possamai, Henrique Cechinel Casagrande, Gilson de March and Paulo Eduardo Ceccacci de Lion

Materials 2026, 19(14), 3003; https://doi.org/10.3390/ma19143003 - 12 Jul 2026

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Abstract

Wire Laser Additive Manufacturing (WLAM) has emerged as a promising alternative for the fabrication and repair of components subjected to severe wear conditions due to its high deposition rate, efficient material utilization, and localized thermal control. In this study, the WLAM process using [...] Read more.

Wire Laser Additive Manufacturing (WLAM) has emerged as a promising alternative for the fabrication and repair of components subjected to severe wear conditions due to its high deposition rate, efficient material utilization, and localized thermal control. In this study, the WLAM process using DUR600 wire as the feedstock material for the deposition of abrasion-resistant coatings was investigated. The deposited specimens were characterized by optical emission spectroscopy (OES), X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), Vickers microhardness testing, and dry sand/rubber wheel abrasion testing in accordance with ASTM G65. The deposits exhibited a predominantly martensitic microstructure with retained austenite, as confirmed by XRD. Hardness values ranged from 749 to 817 HV, with an average of 783 ± 18 HV, while the average volumetric loss in the abrasive wear test was 150.26 mm³. This behavior was attributed to the presence of the martensitic matrix and retained austenite, whose combined effect directly influences the tribological performance of WLAM coatings produced using DUR600 wire. Full article

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

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15 pages, 6175 KB

Open AccessArticle

The Microstructure and Properties of CoCrFeNi/WC-Nb HEA Composite Coating Prepared by Laser Cladding

by Haihong Fan, Zijian Liu, Haomu Zhu, Liancai Pang and Jiang Huang

Materials 2026, 19(13), 2866; https://doi.org/10.3390/ma19132866 - 4 Jul 2026

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Abstract

CoCrFeNi/WC-Nb high-entropy alloy (HEA) composite coating was prepared on the surface of Q235 steel by LC (laser cladding) technology, and the effects of WC and in situ NbC reinforcement on the coating were studied. The phase composition, phase characteristics, microhardness, and wear resistance [...] Read more.

CoCrFeNi/WC-Nb high-entropy alloy (HEA) composite coating was prepared on the surface of Q235 steel by LC (laser cladding) technology, and the effects of WC and in situ NbC reinforcement on the coating were studied. The phase composition, phase characteristics, microhardness, and wear resistance of the cladding coatings were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), friction and wear tester, and X-ray photoelectron spectroscopy (XPS), and the corrosion resistance was tested by a three-electrode electrochemical workstation. The results show that the CoCrFeNi/WC-Nb HEA coating consists of FCC, WC, NbC, and Laves phases, and the reinforcing phase causes grain refinement and lattice distortion. The microhardness reached (418.29 ± 16.72) HV, which was about 2.64-times higher than that of the CoCrFeNi HEA coating. The wear rate decreased to (1.150 ± 0.11) × 10⁻⁴ mm³N⁻¹m⁻¹, which was about 0.25 times that of the CoCrFeNi HEA coating, and the wear of the coating changed from abrasive wear to adhesive wear. The corrosion current density and corrosion voltage of the CoCrFeNi/WC-Nb HEA coating are (3.3820 ± 0.2103) × 10⁻⁶ A/cm² and −(0.7650 ± 0.0850) V, respectively. Full article

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

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27 pages, 52218 KB

Open AccessArticle

Effect of Internal Defects on the Compression Behavior of Helical Layered Square Honeycombs Fabricated by Selective Laser Melting

by Yue Ni, Yangning Li, Wei Chen, Pengcheng Hu, Xiaobin Li, Wenchao Ke and Jianye Du

Materials 2026, 19(12), 2492; https://doi.org/10.3390/ma19122492 - 10 Jun 2026

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Abstract

The emergence of selective laser melting (SLM) has enabled the fabrication of complex structures with exceptional mechanical performance. However, process-induced defects, including porosity and geometric deviations, pose significant challenges to structural reliability, and their dynamic evolution under loading remains poorly understood. In this [...] Read more.

The emergence of selective laser melting (SLM) has enabled the fabrication of complex structures with exceptional mechanical performance. However, process-induced defects, including porosity and geometric deviations, pose significant challenges to structural reliability, and their dynamic evolution under loading remains poorly understood. In this study, helical layered square honeycomb structures were fabricated via SLM. The effects of process conditions on defect characteristics, as well as the influence of porosity and wall thickness defects on mechanical properties, were investigated using X-ray computed tomography (CT), in situ loading tests, and finite element simulation. The results indicate that the investigated high-quality process conditions minimize porosity, optimize pore morphology, and improve wall thickness uniformity, thereby substantially reducing the adverse effects of pores on tensile properties. Under compressive loading, defect evolution, including pore expansion and wall thickness thinning, is primarily concentrated at structural corners, with more pronounced variations observed under coarse process conditions. Increased porosity, wall thickness reduction, and uneven thickness distribution all degrade the quasi-static compressive performance and medium to high-velocity impact resistance of the structure. Furthermore, thickness distribution exerts an independent influence on mechanical properties beyond the effect of overall average thickness. Full article

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

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34 pages, 28818 KB

Open AccessArticle

Effect of Heat Treatment on the Corrosion and Wear Behavior of Hastelloy C276 Alloy Fabricated via Laser Powder Bed Fusion

by Xiao Fang, Zitong Wang, Changqing Ye, Yang Li, Liping Zhang, Jianzhong Yang, Shulong Ye, Xin Shang, Dingning Wang, Dongyu Liu, Shukui Li and Bingwen Lu

Materials 2026, 19(11), 2332; https://doi.org/10.3390/ma19112332 - 1 Jun 2026

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Abstract

Traditional C276 alloy plates exhibit relatively poor wear resistance. Consequently, in high-wear service environments, they typically require reinforcement through additional surface coatings or wear-resistant materials. To further expand the application potential of C276 alloy in marine environments, where both corrosion resistance and wear [...] Read more.

Traditional C276 alloy plates exhibit relatively poor wear resistance. Consequently, in high-wear service environments, they typically require reinforcement through additional surface coatings or wear-resistant materials. To further expand the application potential of C276 alloy in marine environments, where both corrosion resistance and wear resistance are critical, this study utilized L-PBF technology to fabricate C276 alloy specimens. The specimens were subjected to microhardness, room-temperature tensile, electrochemical corrosion, and tribological wear tests under three distinct heat treatment conditions. The results indicate that the precipitation of a Mo/W-rich μ-phase, induced by heat treatment, serves as the key factor in tailoring the material’s properties. Heat treatment was found to significantly enhance both the corrosion resistance and wear resistance of the L-PBF–fabricated C276 alloy. Specifically, the heat treatment process involving holding at 870 °C for 8 h followed by furnace cooling demonstrated the most effective strengthening effect. Under these conditions, both the microhardness and tensile strength were markedly higher than those of traditional plate specimens, thereby significantly improving the material’s damage resistance. Furthermore, the primary wear mechanisms observed in the specimens were adhesive wear and abrasive wear, accompanied by minor oxidative wear. Compared to traditional plate material, the wear rate of the heat-treated L-PBF C276 alloy was significantly reduced. This study demonstrates that appropriate heat treatment processes provide an effective pathway for tailoring the properties of L-PBF–fabricated C276 alloy components, a finding of significant importance for extending their service life and expanding their engineering applications. Full article

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

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19 pages, 6946 KB

Open AccessArticle

Hot Forging of DIN 8555 E6-UM-60 Alloy Produced by Directed Energy Deposition: Understanding the Metallurgical Effects

by Carlos Antônio Ferreira, Lirio Schaeffer, Anderson Daleffe, Henrique Cechinel Casagrande, Gilson de March and Joélson Vieira da Silva

Materials 2026, 19(2), 373; https://doi.org/10.3390/ma19020373 - 16 Jan 2026

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Abstract

This study investigates a hybrid processing route that integrates localized fusion-based additive manufacturing and hot forging for the production of complex-shaped components, with emphasis on metallurgical integrity and mechanical performance. The DIN 8555 E6-UM-60 alloy, traditionally classified as martensitic and applied under severe [...] Read more.

This study investigates a hybrid processing route that integrates localized fusion-based additive manufacturing and hot forging for the production of complex-shaped components, with emphasis on metallurgical integrity and mechanical performance. The DIN 8555 E6-UM-60 alloy, traditionally classified as martensitic and applied under severe wear conditions, exhibited atypical metallurgical behavior during hybrid processing, notably the consistent formation of chromium carbides under specific thermomechanical conditions. Metallographic analyses, microhardness measurements, thermographic monitoring, hot tensile tests, and room-temperature tensile tests were performed to establish correlations between microstructure, thermal history, and mechanical response. Specimens produced by additive manufacturing and subsequently hot forged showed a significant reduction in porosity, improved microstructural homogeneity, and partial retention of hardening phases, enabling discussion of recrystallization mechanisms, phase stabilization, and precipitation phenomena in martensitic alloys processed by additive manufacturing. Hot tensile tests revealed limited hot workability of the alloy, while room-temperature tensile tests led to premature fracture, with failure consistently initiating at pre-existing microcracks formed during the forging stage. Although detrimental, these microcracks provide valuable insight into critical processing conditions and ductility limits of the material. Overall, the hybrid route demonstrates strong potential for industrial applications, highlighting the importance of precise thermomechanical cycle control to mitigate defects and enhance structural reliability. Full article

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

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18 pages, 5679 KB

Open AccessArticle

Effect of Fe and Si Content on Microstructure, Mechanical Properties, and Corrosion Resistance of 7050 Alloy

by Changlin Li, Wei Zhao, Tingrui Zhang, Xiwu Li, Zhicheng Liu, Ying Li, Lizhen Yan, Pengfei Xu, Kai Wen, Yongan Zhang, Zhihui Li and Baiqing Xiong

Materials 2026, 19(1), 135; https://doi.org/10.3390/ma19010135 - 30 Dec 2025

Cited by 4 | Viewed by 1359

Abstract

In this work, the effect of Fe and Si content on microstructure, mechanical properties, and corrosion resistance of 7050 alloy was systematically investigated by room temperature tensile, fracture toughness, and exfoliation corrosion tests, complemented by microstructural characterization through SEM and TEM. The results [...] Read more.

In this work, the effect of Fe and Si content on microstructure, mechanical properties, and corrosion resistance of 7050 alloy was systematically investigated by room temperature tensile, fracture toughness, and exfoliation corrosion tests, complemented by microstructural characterization through SEM and TEM. The results demonstrate that the impurity elements Fe and Si induce the formation of insoluble Fe-rich phases and Mg₂Si phases in the alloy, respectively. The coexistence of Fe and Si leads to a severe synergistic deterioration effect on mechanical properties. Furthermore, the study reveals that Si has a more profound negative impact on mechanical properties than Fe. While Fe primarily reduces ductility and fracture toughness by initiating microcracks through Fe-rich phases with minimal effect on strength, Si not only forms brittle Mg₂Si phases that impair toughness but also significantly depletes the Mg content in the matrix, thereby reducing the quantity of strengthening phases. This results in a comprehensive and severe decline in strength, plasticity, and toughness. In addition, Fe and Si impurities markedly degrade the exfoliation corrosion resistance of the alloy. Full article

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

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Review

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30 pages, 1099 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

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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)

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