ZA27合金的铸态组织及晶界共晶体

The Cast Structure and Eutectic Formed Along the Grain Boundary in ZA27 Alloy

研究分析了ＺＡ２７合金（锌－铝合金）的铸态组织及其分布特点．电子探针分析表明ＺＡ２７合金的初生α相和β相晶内偏析十分严重；在电镜下观察可见α相和β相已转变成层片相间的（α＋η）共析体．并从差热分析、微区分析等四个方面着重讨论了ＺＡ２７合金的晶界不平衡组织是共晶体（由α，β，η相组成），而不是共析体．退火处理可以消除晶界不平衡共晶体，并使成分均匀化，从而使ＺＡ２７合金的塑性得到明显提高．

The authors have researched and analysed the cast structure and it's distributing feature ofZA27 alloy.The results of electron mieroprobe analysis shows that the coring is quite obviousin α andβphases in the alloy.And under electron microscope,αandβphases have changedinto eutectic which is composed of altemative α and ηlamellae. Besides,according to theresults of differential thermal analysis,microanalysis and so forth.the authors demonstrate thatthe non-equilibrium structure formed along grain boundary is eutectic which consists of α,βandηphases instead of eutectoid.Annealing can elminate the coring and the eutectic existedalong grain boundary,which makes ZA27 alloy plasticity increase greatly.