供应态LY12CZ铝合金在超塑性形变中晶界形态的研究

Study on Grain Boundary Morphology in Commercial LY12CZ Aluminum Alloy During Superplastic Deformation

采用光学显微镜、扫描电镜和透射电镜对未经任何预处理、晶粒尺寸为 19μm～ 2 1μm之间的供应态LY12CZ铝合金超塑性形变中晶界形态进行了观察、分析。结果表明 ,此状态下的铝合金在超塑性变形过程中晶界宽度和形态会发生改变。在较大伸长率的条件下 ,晶界出现宽边化和圆弧化。在超塑性变形过程中形成的宽边晶界属于介稳状态的界面 ,在高温下短时间保温 ,宽边晶界会发生晶化 ,变成细小的普通晶界。试样在超塑性变形时产生的伸长率与晶界宽度有密切联系。在此次试验中超塑性伸长率大的试样其晶界宽度在 2 1μm～2

The evolvement of grain boundary morphology in commercial LY12CZ aluminum alloy with grain size between 19μm～21μm and non-pretreatment during superplastic deformation was observed and analyzed by optics microscope,SEM and TEM.The results showed that grain boundary width and grain boundary form of the aluminum alloy would change during superplastic deformation.With bigger elongation,all boundary of grain appeared widening and being round arc.While the new wider boundary formed during superplastic deformation as of sub-stable interface.This kind of boundary will become thin and usual grain boundary by crystallization when keep it at high-temperature for a moment.Elongation of the sample during superplastic deformation has a close relation with grain boundary width.Grain boundary width of big elongation sample in the experiment is between 2.1μm and 2.7μm.