AZ31B合金的铸轧组织

Microstructure of roll casting for AZ31B alloy

利用金相及扫描电镜对AZ31B合金热模拟和铸轧样组织结构进行研究。研究结果表明:在不同应变量下,热模拟样品的晶粒粒度均随应变速率的增加而减小,而当其他条件相同时,变形量越大晶粒粒度越小,冷却强度降低,合金呈典型铸态组织;利用铸轧技术生产的AZ31B合金,当应变速率一定时,随着初始铸轧温度的降低,铸轧态板材的树枝晶粒度逐渐减小;而在初始铸轧温度一定时,随着应变速率的增大,铸轧态合金板材的树枝晶粒度也逐渐减小;而随着应变速率的提高,树枝晶沿轧向呈流线状排列的趋势增强;在AZ31B合金铸轧过程中,轧制力不能太大,否则容易引起热裂。

The microstructures of thermal simulation and roll casting AZ31B alloys were investigated by optical microscope （OM） and scanning electron microscopy （SEM） observation. The results show that with the increase of strain rate, the grain sizes of thermal simulation AZ31B alloys with different deformation all decrease; however, when other conditions are the same, the higher deformation will lead to the formation of the smaller grain size, and as the cooling intensity decreases, typical cast structure of AZ31B will appear. With the decrease of roll casting temperature, the dendritic size of roll casting AZ31B alloy sheet prepared by the same strain rate is also reduced, but with the increase of strain rate, the dendritic size of the alloy sheet prepared by the same initial roll casting temperature is decreased, and the tendency of dendritic streamline is strengthened. During the roll casting process ofAZ31B alloy, rolling force should not be large, otherwise it will cause heat cracking.