Cu－Zn－Al合金初生态贝氏体的台阶普遍性

GENERAL EXISTENCE OF LEDGES OF INITIAL BAINITES IN Cu-Zn-Al ALLOYS

利用透射电镜（ＴＥＭ）观察了三种不同成分的Ｃｕ－Ｚｎ－Ａｌ合金在不同等温温度（２５０，３００，３５０℃）下形成的贝氏体的显微结构．结果发现，三种合金在不同温度形成的贝氏体初生态的宽面及端面均存在三维形态的台阶，但无层错亚结构，表明台阶在Ｃｕ－Ｚｎ－Ａｌ合金贝氏体中是普遍存在的，贝氏体的生长属扩散控制的台阶长大机制．

The microstructures of bainites in three composition Cu-Zn-Al alloys formed at 250, 300 and 350℃ were investigated by means of transmission electron microscopy (TEM). The results show that all the initial bainites formed in different alloys at different temperatures are with three-dimensional ledges on the broad faces and/ or at the growth edges of α1 plates but without internal stacking faults, which proves that ledges exist generally on bainites in Cu-Zn-Al alloys and that the growth of bainites is governed by a diffusion-controlled ledgewise mechanism.