摘要
利用ＴＥＭ研究了两种定向凝固共晶合金ＮｉＡｌ－Ｃｒ和ＮｉＡｌ－（Ｃｒ，Ｍｏ）在不同状态下的显微结构特征，以能了解其复相强韧化作用。它们的显微结构分别呈棒状和层状形态。共晶两相间的界面呈半共格，存在不可动的位错网。此外，在（Ｃｒ，Ｍｏ）相上分布着细小的共格ＮｉＡｌ析出相。经形变后，ＮｉＡｌ相中的位错被界面位错网钉扎，（Ｃｒ，Ｍ０）相中未发现位错。经１３００Ｋ×５００ｈ热处理，共晶形态稳定不变，ＮｉＡｌ析出相稍显粗化。
Directionally solidified NiAl-Cr and NiAl-(Cr,Mo) eutectic alloys were studied by TEM to characterize their microstructures. The microstructures showed a rod-like and lamellar morphology, respectively. The interphase boundaries between the eutectic phases are semicoherent and composed of a welldefined dislocation network. In addition, fine coherent NiAI precipitates were dispersed throughout the (Cr, Mo) phase.After deforniationdislocations in NiAl phase were pinned by the interface dislocation network. No dislocation in(Cr,Mo) phase was observed. The eutectic morphology was stable at 1300K with only coarsening of the NiAl precipitates after heat treatment for 500h.
关键词
定向凝固
共晶形貌
界面
位错网
共晶合金
NiAl-Cr, NiAl-(Cr, Mo), directional solidification, eutectic morphology, interface dislocation network
