γ′[Ni3(Ti,Al)]沉淀相强化Fe-Ni基奥氏体合金兼具较高强度和可接受的抗氢脆性能被视为未来临氢工作材料的最佳选择之一。虽然这种合金只是在单相奥氏体抗氢合金基础上析出了强化相γ′，但其氢致面缩损减率从单相奥氏体合金的10%以下增加到30%以上。前期研究表明γ′相与基体界面共格状态对合金的氢脆敏感性有重要影响，但相关机理目前尚不清楚。本申请拟结合动态充氢慢应变速率拉伸、三维原子探针氢元素分布表征、透射电镜γ′/γ相界面表征等手段着重研究：(1) γ′/γ相界面共格状态对氢原子在γ′/γ相界面及γ′相内部富集的影响；(2)充氢条件下运动位错与不同共格状态γ′相交互作用的差异及其对合金氢脆机制的影响。综合以上两方面研究揭示γ′/γ相界面共格状态对合金氢脆敏感性的影响机理，为Fe-Ni基沉淀强化奥氏体合金焊件性能的优化奠定理论基础，也为新型更高性能抗氢合金及其焊接工艺的开发提供理论参考。

Precipitation-strengthening Fe-Ni based austenitic alloy containing the γ′[Ni3(Ti,Al)] phase is one of the best choices for future applications in critical hydrogenated environment, because of its high strength and acceptable low hydrogen embrittlement sensitivity (HES). Although this alloy is derived from single-phase austenitic hydrogen-resistance alloy coupling with the γ′ precipitations, the hydrogen-induced surface shrinkage reduction rate of such alloy can reach 30% which is much higher than that of single-phase austenitic hydrogen-resistant alloy (<10%). Previous studies demonstrate that HES is significantly influenced by the lattice coherency between the γ′ phase and the austenite matrix. However, the underlying mechanism of this is elusive. Here, by conducting low strain-rate dynamic-hydrogenation tensile tests, characterizing hydrogen element distribution with three-dimensional atom probe tomography and exploring γ′/γ phase interface with transmission electron microscope, we intend to address two scientific issues as follows: (1) Dependence of hydrogen segregation in the γ′ phase and γ′/γ interface on the γ′/γ interfacial coherency. (2) Dependence of dislocation slip behaviors on the γ′/γ interfacial coherency during dislocations interaction with hydrogenated γ′ phase. Thereby, the research will uncover the underlying mechanism on how γ′ precipitation, particularly the γ′/γ interfacial coherency, affects the hydrogen embrittlement sensitivity. In addition to laying the theoretical foundation for the performance improvement of Fe-Ni based precipitation-hardening austenitic alloy weldments, this research will provide a theoretical reference for developing better hydrogen-resistant structural alloys.