定向凝固NiAl—28Cr—5.5Mo-0.5Hf合金中Ni_2AlHf相和Ni_(16)Hf_6Si_7相的研究

INVESTIGATION OF HEUSLER PHASE Ni2AlHf AND G-PHASE Ni16Hf6Si7 IN A DIRECTIONALLY SOLIDIFIED NiAl-28Cr-5.5Mo-0.5Hf ALLOY

少量的Ｈｆ（０．５％）加入到定向凝固的ＮｉＡｌ－Ｃｒ（Ｍｏ）合金中，会产生Ｈｅｕｓｌｅｒ相Ｎｉ２ＡｌＨｆ，该相呈网状分布在ＮｉＡｌ／Ｃｒ（Ｍｏ）相界面区域．Ｎｉ２ＡｌＨｆ与ＮｉＡｌ之间不存在固定的晶体学取向关系，但有时也发现二者存在立方－立方取向关系：［１１１］ＮｉＡｌ［１１１］Ｈ，（１０１）ＮｉＡｌ／／（２０２）Ｈ，并通过高分辨电子显微照片分析了二者界面的精细结构由于定向凝固过程中，Ｓｉ元素进入到合金中，所以在此合金中发现了Ｇ－相Ｎｉ１６Ｈｆ６Ｓｉ７．细小弥散的Ｎｉ１６Ｈｆ６Ｓｉ７相呈立方体形状，与Ｎｉ２ＡｌＨｆ相相伴分布在ＮｉＡｌ／Ｃｒ（Ｍｏ）相界面附近同时讨论ＴＮｉＡｌ／Ｎｉ２ＡｌＨｆ及ＮｉＡｌ／Ｎｉ１６Ｈｆ６Ｓｉ７的界面能量。

Small addition(0.5%) of Hf to directionally solidified NiAl-Cr(Mo) alloy results in discontinuously distributed Heusler phase Ni2AlHf at NiAl/Cr(Mo) interface. There is no consistent orientationrelationship(O.R.) between NiAl and Ni2AlHf, but sometimes, a cube-on-cube O.R. was observed betweenthe two phases, [111]NiA,