用正电子湮没技术研究Zr对Ni_3Al缺陷态的影响

PAT STUDY OF EFFECT OF Zr ON DEFECTS IN Ni_3Al ALLOY

本文用正电子湮没技术（ＰＴＡ）研究了含不同ｚｒ量多晶Ｎｉ３Ａｌ的ｅ＋寿命谱。结果表明：在Ｎｉ３Ａｌ中加入Ｚｒ，一部分Ｚｒ原子进行原子替位，使晶格发生畸变，导致基体中正电子寿命（τ_１）增长；另一部分在晶界偏聚的Ｚｒ调整了晶界结构，使平均寿命（τ）下降。当Ｚｒ量为１．２ａｔ．－％时，缺陷态的寿命τ２显著增长，表明有自由体积较大的缺陷组态生成．

The effects of Zr on the microdefects in polycrystalline Ni3Al alloys have been investigated by positron annihilation technique (PAT). The results showed that the lifetime (t1) of positron (e+) in matrix dilated because some of Zr atoms substituted for Al sublattice distorted lattice; the mean lifetime decreased because the others of Zr atoms segregated at GB changed its structure. If Zr was increased up to 1.2 at.-%.t2 increased considerably and it means that defects with larger free volume formed.