Incorporating solute hydrogen into Fe–Cr–Ni-based austenitic stainless steels enhances both strength and ductility, providing a promising solution to hydrogen embrittlement by causing solid-solution strengthening and assisting deformation twinning. However, its impacts on the relevant lattice defects evolution (i.e., dislocations, stacking faults, and twins) during deformation remains unclear. This study compared the tensile deformation behavior in an Fe–24Cr–19Ni (mass%) austenitic steel with 7600 atom ppm hydrogen-charged (H-charged) and without hydrogen-charged (non-charged) using in situ neutron diffraction. Hydrogen effects on the lattice expansion, solid-solution strengthening, stacking fault probability, stacking fault energy, dislocation density, and strain/stress for twin evolution were quantitatively evaluated to link them with the macroscale mechanical properties. The H-charged sample showed improvements in yield stress, flow stress, and uniform elongation, consistent with earlier findings. However, solute hydrogen exhibited minimal influences on the evolution of dislocation and stacking fault. This fact contradicts the previous reports on hydrogen-enhanced dislocation and stacking fault evolutions, the latter of which can be responsible for the enhancement of twinning. The strain for twin evolution was smaller in the H-charged sample compared to the non-charged one. Nevertheless, when evaluated as the onset stress for twin evolution, there was minimal change between the two samples. These findings suggest that the increase in flow stress due to the solid-solution strengthening by hydrogen is a root cause of accelerated deformation twinning at a smaller strain, leading to an enhanced work-hardening rate and improved uniform elongation.

中文翻译：

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溶质氢对 Fe–24Cr–19Ni 奥氏体钢力学性能增强的作用：原位中子衍射研究


将溶质氢掺入 Fe-Cr-Ni 基奥氏体不锈钢中可以提高强度和延展性，通过引起固溶体强化和协助变形孪晶，为氢脆提供有前途的解决方案。然而，它在变形过程中对相关晶格缺陷演变（即位错、堆叠断层和孪晶）的影响仍不清楚。本研究使用原位中子衍射比较了具有 7600 原子 ppm 充氢（H-charged）和无充氢（不带电）的 Fe-24Cr-19Ni（质量%）奥氏体钢的拉伸变形行为。定量评估了氢对孪晶进化的晶格膨胀、固溶体强化、堆叠故障概率、堆叠故障能量、位错密度和应变/应力的影响，以将它们与宏观力学性能联系起来。H 电荷样品在屈服应力、流动应力和均匀伸长率方面表现出改善，与早期的研究结果一致。然而，溶质氢对位错和堆积断层的演变影响最小。这一事实与之前关于氢增强位错和堆叠断层演变的报道相矛盾，后者可能是孪晶增强的原因。与未带电的样品相比，H 带电样品中孪生的演化应变更小。然而，当评估为双胞胎进化的起始应力时，两个样本之间的变化很小。这些发现表明，由于氢的固溶体强化而导致的流动应力增加是在较小应变下加速变形孪晶的根本原因，从而导致加工硬化速率提高和均匀伸长率提高。