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通过测量Ｂ含量从０．００至２．２２ａｔ％的单晶和多晶Ｎｉ＿３Ａｌ合金的正电子寿命谱，研究了单晶和多晶Ｎｉ＿３Ａｌ合金中的微观缺陷和电子结构。结果表明，多晶Ｎｉ＿３Ａｌ合金晶界中存在着开空间大于空位的缺陷。晶界缺陷处参与形成Ｎｉ－Ｎｉ和Ｎｉ－Ａｌ键的价电子浓度比基体或位错处的低，晶界是结合力弱化区域。偏聚到Ｎｉ＿３Ａｌ合金缺陷上的Ｂ与缺陷处的Ｎｉ或Ａｌ原子形成强的共价键而增强了这些地方的结合力。以间隙方式固溶到Ｎｉ＿３Ａｌ基体中的Ｂ与它近邻的Ｎｉ或Ａｌ原子交互作用导致了基体中价电子浓度升高，键结合力增强。
The microscopic defects and electronic structures in single and polycrystalline Ni_3Al alloys were investigated by measuring their positron lifetime spectra from 0.00 to 2.22 at%. The results show that there is a defect that the open space is larger than the vacancy in the polycrystalline Ni_3Al alloy grain boundaries. The grain-boundary defects are involved in the formation of Ni-Ni and Ni-Al bonds with lower valence electron concentrations than those at the matrix or dislocations, and the grain boundaries are areas of weakened bond strength. B segregated to the defects of Ni_3Al alloy formed strong covalent bonds with the Ni or Al atoms in the defect and enhanced the binding force in these places. The interstitial solid solution of B into the Ni 3 Al matrix interacts with its neighboring Ni or Al atoms, leading to an increase in the valence electron concentration in the matrix and an increase in bond strength.