有序态和无序态Ni_3Mn的环境氢脆

Environmental Embrittlement of Ordered and Disordered Ni_3Mn

研究了有序和无序Ni3Mn在室温下不同气氛(真空、空气、和氢气)中的力学性能.结果表明:有序态和无序态Ni3Mn不存在明显的由空气中水汽诱发的环境氢脆;在氢气气氛中,两者均存在明显的环境氢脆现象,且无序态脆性程度略高于有序态.有序Ni3Mn的拉伸曲线存在明显的屈服平台,而无序态没有.有序态强度高于无序态.扫描电镜观察表明:无序态和有序态Ni3Mn在真空和空气中全部为韧性断口.在氢气中,无序态基本为沿晶断口,而有序态则表现为穿晶和沿晶混合断口.

The mechanical properties of ordered and disordered Ni_3Mn in various atmosphere (va-(cuum, air ) and H_2) at the room temperature have been investigated. The results show that there is no moisture-induced environmental embrittlement for ordered and dis-(ordered) Ni_3Mn when tested in the air. The results also indicate that there is obvious environmental embrittlement for ordered and dis-(ordered) Ni_3Mn when they are tested in H_2, and the embrittlement of disordered Ni_3Mn is more severe than that of ordered Ni_3Mn. There is a yield platform in the engineering stress-strain curve of ordered Ni_3Mn, however, no similar phenomenon has been observed in disordered Ni_3Mn. The strength of ordered Ni_3Mn is greater than that of disordered Ni_3Mn.The fracture modes of ordered and disordered Ni_3Mn in vacuum and in air are all ductile. In H_2 the fracture mode of disordered Ni_3Mn is intergra-(nular,) while the ordered Ni_3Mn shows a mixed mode of intergranular and transgranular fracture.