Ni－Al金属间化合物的快速凝固组织与室温塑性

Morphology and Ductility of Melt-Spun Ni-Al Intermetallics

运用熔体旋转法研究了Ｎｉ－３１ａｔ．％～３７ａｔ．％Ａｌ的快速凝固组织及其室温塑性。结果表明，Ｎｉ－３４ａｔ．％Ａｌ和Ｎｉ－３７ａｔ．％Ａｌ快速凝固时形成等轴晶组织，Ｎｉ－３１ａｔ．％Ａｌ倾向于形成柱状晶组织。其中Ｎｉ－３７ａｔ．％Ａｌ组织全部为马氏体，Ｎｉ－３４ａｔ．％Ａｌ除形成马氏体外，晶界上尚有少量Ｎｉ３Ａｌ相，Ｎｉ－３１ａｔ．％Ａｌ则得到亚稳态层片状组织。Ｎｉ－３７ａｔ．％Ａｌ具有１．４％的伸长率，Ｎｉ－３４ａｔ．％Ａｌ和Ｎｉ－３１ａｔ．％Ａｌ的伸长率仅有０．８％和０．６％。分析了ＮｉＡｌ金属间化合物的组织形成规律和增塑机制。

The morphology and ductility of Ni-31at.%Al～37at.%Al alloys were investigated by melt-spun technology. The results show that the alloys with the composition of Ni-34at.%Al and Ni-37at.%Al exhibit equiaxed grains,and Ni-31at.%Al columnar grains, For Ni-37at.%Al,complete martensite can be obtained;whereas for Ni-34at.%Al,except martensite there is still Ni3Al on the grain boundaries;and for Ni-31at.%Al,metastable lamellar structure exists. Ni37at.%Al exhibits an elongation of 1.4%, but the elongation of Ni-31at.%Al and Ni-34at.%Al is only 0.8% and 0.6% respectively.The mechanisms of phase formation and ductility enhancement are put forward.