Stress and temperature, rather than hydrogen, govern stacking fault evolution during tensile deformation in Fe-24Cr-19Ni steel

Ito, Tatsuya; Ogawa, Yuhei*; Gong, W.; Kawasaki, Takuro; Shibata, Akinobu*; Harjo, S.

Scripta Materialia, 273, p.117084_1 - 117084_6, 2026/03

https://doi.org/10.1016/j.scriptamat.2025.117084

Low-temperature deformation mechanism in a work-hardenable body-centered cubic high-entropy alloy with a large uniform elongation

Zhu, L.*; Dong, W.*; Naeem, M.*; Kong, H.*; Hu, C.*; Fan, Z.*; Gong, W.; Harjo, S.; Lan, S.*; Wu, Y.*; et al.

Acta Materialia, 303, p.121734_1 - 121734_10, 2026/01

https://doi.org/10.1016/j.actamat.2025.121734

Mechanistic origin of oxygen-induced twin suppression in titanium

Chong, Y.*; Tsuru, Tomohito; Gholizadeh, R.*; Minor, A. M.*; Tsuji, Nobuhiro*

Acta Materialia, 301, p.121523_1 - 121523_12, 2025/12

https://doi.org/10.1016/j.actamat.2025.121523

Twinning is essential for achieving large ductility in hexagonal close-packed (HCP) titanium alloys that inherently lack independent slip systems due to an asymmetrical HCP crystal structure. Unfortunately, twinning is in principle suppressed by a trace amount of interstitial oxygen, resulting in a substantially deteriorated ductility in titanium. However, the underlying mechanism remains in dispute so far. Here, we report a systematic multiscale study on the twinning/detwinning behaviors of Ti-O alloys that provides a clear mechanistic view of how interstitial oxygen inhibits twinning. We reveal for the first time that oxygen atoms segregate to both {102}2} compression twin boundaries using atom probe tomography. Combined with theoretical simulations that unravel a strong pinning effect of oxygen atoms on twin boundary due to an oxygen shuffling mechanism, we explain the distinctive migration abilities of twin boundaries in Ti-O alloys at different temperatures. The insights from our experimental and computational work provide a rationale for the design of titanium alloys with increased tolerance to variations in interstitial impurity content, with significant implications for more widespread use of this high strength, light weight material.

First-principles calculations of hydrogen trapping energy at an edge dislocation core in iron

Yamaguchi, Masatake; Ebihara, Kenichi; Itakura, Mitsuhiro

Scripta Materialia, 268, p.116887_1 - 116887_6, 2025/11

https://doi.org/10.1016/j.scriptamat.2025.116887

Extraordinary hardening-by-annealing in bulk ultrafine grained magnesium with ultra-low yttrium addition

Zheng, R.*; Gong, W.; 6 of others*

Acta Materialia, 293, p.121098_1 - 121098_12, 2025/07

https://doi.org/10.1016/j.actamat.2025.121098

Complementary layer thickness effects of Q235 and SUS304 layers of multilayered steels for improving of tensile strength and plasticity simultaneously

Lin, Z. M.*; Liu, B. X.*; Ming, K. S.*; Xu, P. G.; Yin, F. X.*; Zheng, S. J.*

Scripta Materialia, 263, p.116692_1 - 116692_7, 2025/07

https://doi.org/10.1016/j.scriptamat.2025.116692

Grain refinement of dual phase steel maximizes deformation ability of martensite, leading to simultaneous enhancement of strength and ductility

Park, M.-H.*; Shibata, Akinobu*; Harjo, S.; Tsuji, Nobuhiro*

Acta Materialia, 292, p.121061_1 - 121061_13, 2025/06

https://doi.org/10.1016/j.actamat.2025.121061

On the role of austenite stability in yielding behavior of a medium Mn steel with a duplex austenite-martensite microstructure

Wang, Y.*; Gong, W.; Harjo, S.; 7 of others*

Acta Materialia, 288, p.120840_1 - 120840_14, 2025/04

https://doi.org/10.1016/j.actamat.2025.120840

Quantitative estimation method of the effect of segregated solute on hydrogen-enhanced decohesion at a grain boundary

Yamaguchi, Masatake; Ebihara, Kenichi; Itakura, Mitsuhiro; Tsuru, Tomohito

Scripta Materialia, 255, p.116366_1 - 116366_5, 2025/01

https://doi.org/10.1016/j.scriptamat.2024.116366

Reduction of grain boundary cohesive energy by hydrogen has been considered as one of the candidate causes of grain boundary fracture in steels and aluminum alloys. Recently, the effects of grain boundary segregation elements have been investigated by first-principles calculations, but there are few studies that quantitatively estimate the grain boundary cohesive energy. In this study, we describe a quantitative evaluation method using first-principles calculation results and show some examples of experimental calculations.

Martensitic transformation-governed Luders deformation enables large ductility and late-stage strain hardening in ultrafine-grained austenitic stainless steel at low temperatures

Mao, W.*; Gao, S.*; Gong, W.; Kawasaki, Takuro; Ito, Tatsuya; Harjo, S.; Tsuji, Nobuhiro*

Acta Materialia, 278, p.120233_1 - 120233_13, 2024/10

https://doi.org/10.1016/j.actamat.2024.120233