NiAl金属间化合物的快速凝固组织

THE MORPHOLOGY OF RAPIDLY SOLIDIFIED NiAl INTERMATALLICS

用单辊快速凝固法制备了Ｎｉ原子分数为０．５３—０．６０的Ｎｉ－Ａｌ金属间化合物薄带，研究了成分与微观组织的关系．发现试样均为Ｂ２型单相Ｎｉａｌ，Ｎｉ＿（０．５３）Ａｌ＿（０．４７）的快速凝固组织为１０μｍ左右的等轴晶．Ｎｉ＿（０．５６）Ａｌ＿（０．４４）—Ｎｉ＿（０．６）Ａｌ＿（０．４）的组织分别为５μｍ左右的不规则和规则柱状晶．发现近理想配比的ＮｉＡｌ在快速凝固时形成计状晶亚结构．

The ribbons of Ni0.53 Al0 .47 Ni0.6 Al0.4 intermatallic compounds have been prepared by single roller rapidly solidified technology.Their composition and morphology have been investigated.TEM shows that the ribbons have the B2 structure;SEM shows that the rapidly solidified morphology of Ni0.53 Al0.47 is about 10μm equiaxed crystals whereas those of 0.56- 0.60 Ni are 5μm irregular and regular colmnar crystals,respectively.It is observed that under the condition of rapidly solidifying, a new substructure-needle-like crystal can be get with the near stoichiometric composition.