氢对316H不锈钢拉伸性能的影响

Influence of hydrogen on tension property of 316H stainless steel

采用慢应变拉伸试验研究了氢对时效前后316H不锈钢拉伸行为的影响,利用扫描电子显微镜观察了不同氢含量下光滑试样和缺口试样的断口形貌特征。结果表明,热处理状态不会对饱和氢含量产生显著的影响,具体来说,析出相及析出相/基体界面对饱和氢含量影响有限。氢增强了应变诱导的空位的产生,提高了合金的氢致面缩损减,降低了塑性。与固溶态韧窝状的断口形貌相比,时效后的断口形貌呈现"韧窝+二次裂纹+准解理"特征。可以推测,时效形成的σ相/基体界面作为氢的陷阱,其与应力集中共同作用,加剧了氢致塑性的损减。

The effects of hydrogen on the tensile behavior of 316 H stainless steel before and after aging were studied by slow strain tensile test. The fracture morphology of smooth and notched specimens with different hydrogen contents were observed by scanning electron microscopy. The results show that heat treatment state does not have a significant effect on the saturated content of hydrogen. Specifically, the precipitation phase and the precipitation phase/matrix interface have a limited effect on the saturated solubility of hydrogen. Hydrogen enhances the generation of strain-induced vacancies, improves the hydrogen-induced surface shrinkage reduction of the alloy, and reduces plasticity. Compared with the solid-state dimple-like fracture morphology, the fracture morphology after aging exhibits the characteristics of "dimple + secondary crack + quasi-cleavage" in solution treated condition. It can be speculated that the interface between the σ phase and the matrix formed during aging acts as sinks for hydrogen, which enhances the hydrogen induced ductility loss with the stress correntration.