氢对Ni_3Al合金中微观缺陷的影响

Effect of hydrogen on microdefects in Ni 3Al alloys

对二元Ｎｉ３Ａｌ和含０．５２ａｔ．％Ｂ的Ｎｉ３Ａｌ合金样品进行电解充氢，并测量其ｅ＋寿命谱。结果可见，ｅ＋在合金缺陷中的寿命最初随充氢时间的增加而下降，随后达到一个最小值，接着随充氢时间的增加而增加。含０．５２ａｔ．％Ｂ的Ｎｉ３Ａｌ合金比二元Ｎｉ３Ａｌ合金的氢效应程度小。这说明加入少量的硼可提高Ｎｉ３Ａｌ合金的抗氢能力。

The cathodic charging of hydrogen into binary Ni 3Al and Ni 3Al with 0.52at.% B has been investigated by measuring the positron lifetime spectra. It is found that the alloys with hydrogen atoms initially migrated to the pre-existent defects result in the decrease of lifetime of positrons in the defects. With the increase of H-charging time, more hydrogen atoms are accumulated at the defects, subsequently forming the gaseous hydrogen molecules with high pressure to generate larger open-volume defects,thus increasing positrons' lifetime. Hydrogen effects are weaker in Ni25;337;Al with 0.52at.% B as compared with those in binary Ni25;337;Al alloy, which indicates that the addition of B atoms could suppress hydrogen-harmful effect in Ni 3Al alloys.