采用正电子湮没寿命谱研究了氢在不同热处理状态的Fe-Ni基沉淀强化奥氏体合金中的占位规律和作用机制, 结合拉伸实验、扫描电镜和透射电镜观察研究了热处理和热充氢对合金微观组织及力学性能的影响. 结果表明：热充氢导致固溶态合金内部的空位团浓度升高,合金强度上升, 塑性略有下降；氢在峰值时效合金中不进入γ'/γ界面,而是主要进入含少量碳化物的晶界和晶内空位团, 使合金塑性显著降低；过时效处理产生粗大γ'相, 使γ'/γ界面成为氢陷阱, 同时氢还进入存在连续碳化物的晶界, 造成合金塑性的严重降低.
Positron annihilation lifetime and SEM were used to study the change of internal defects before and after hydrogen charging in a Fe-Ni based precipitation strengthened austenitic stainless steel which was heat-treated under different conditions. Positron annihilation lifetime spectrum was fitted in terms of two lifetime components. Both positron annihilation lifetime and tensile tests at room temperature indicate that solution treated alloy has a very little grain-boundary carbide and hydrogen charging will increase its strength while decrease its plasticity. Peak aging will produce more grain-boundary carbide and the phase is in the size below 20nm，but is coherent with the matrix. After hydrogen charging, hydrogen will not enter the - interface，but the grain boundary and inter-grain vacancy clusters resulting in a obvious drop of plasticity, over-aging will induce much more interconnected grain-boundary carbide and will coarse in a size of more than 70nm. As a result, hydrogen will enter the grain boundary and - interface with dislocation, which leads to the dramatic drop of plasticity.
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