Zr对Ni3Al晶界及力学性能的影响

对不同Ｚｒ含量Ｎｉ３Ａｌ的力学性能及晶界的研究结果表明：随Ｚｒ含量的增加，合金的屈服强度和抗张强度不断提高；当Ｚｒ≤０．７ａｔ．－％时，塑性随Ｚｒ含量的增加而提高；但Ｚｒ含量达１．２ａｔ．－％时，Ｚｒ的增塑效果下降．Ａｕｇｅｒ能谱分析表明：Ｚｒ在晶界有偏聚，偏聚因子约为３．断口观察显示：不含Ｚｒ或Ｚｒ含量为１．２ａｔ．－％的Ｎｉ－２４．０Ａｌ合金均为沿晶断裂，其余含Ｚｒ合金的断裂方式为穿晶、沿晶混合断裂．这表明：含Ｚｒ的Ｎｉ３Ａｌ塑性和Ｚｒ在晶界的偏聚有密切关系．

EFFECTS OF Zr ON GRAIN BOUNDARY AND MECHANICAL PROPERTIES IN Ni_3Al ALLOYS

The yield and ultimate strengths increase with the amount of Zr increasing. If an additive of Zr less than 0.7 at.-%. the elongation of the alloy increases with Zr content growing. If Zr added up to 1.2 at-%. the effect of Zr improving ductility of the alloy is fall off. Auger study indicated that the amount of Zr segregated to the GB is about 3 times greater than that in the bulk. SEM investigation showed that the fracture mode changes from intergranular in Ni-24.0 Al and Ni-24.0 Al-1.2Zr (in at.-%) alloys to the mixed of interand trans-granular in Ni-24.0 Al-0.3 Zr and Ni-24.0 Al-0.7 Zr (in at.-%) alloys. These results manifested that the effect of Zr improving the ductility in Ni3Al has strong relationship with the segregation of Zr at GB.