B对无序态和有序态Ni_3Fe合金环境氢脆的影响

Effect of B doping on environmental embrittlement of disordered and ordered Ni_3Fe alloys

为了阐明金属间化合物中H2所致脆性的机理及B在抑制这类氢脆的作用,研究了B对无序态和有序态Ni3Fe合金氢脆的影响及其预渗氢后断口沿晶深度的影响。结果表明:B能同时降低H在无序态和有序态Ni3Fe合金中的表观扩散系数,而且不管是否添加B,H在无序态Ni3Fe合金中的表观扩散系数始终大于H在有序态Ni3Fe合金中的表观扩散系数。因此,不能简单地从B影响Ni3Fe合金中H扩散来解释B能明显抑制有序态Ni3Fe合金在H2中的环境氢脆。

In order to understand the mechanism of H2-induced environmental embrittlement and boron effect on inhibitting this kind of embrittlement in intermetallics, the effects of boron doping on the sensitivity to environmental embrittlement of disordered and ordered Ni3Fe alloys and on its intergranular depth after hydrogen charging were investigated. The results show that boron can similarly reduce hydrogen diffusion along grain boundary in both disordered and ordered Ni3Fe alloys. The hydrogen diffusion coefficient in disordered Ni3Fe alloy is always larger than that in ordered Ni3Fe alloy with or without boron. This suggests that the effect of boron on suppressing H2-induced environmental embrittlement in ordered Ni3Fe alloys can not be simply attributed to the fact that boron retards hydrogen diffusion along grain boundaries.