热变形对Mg-9Zn-2Gd-1Y合金微观组织的影响

Effect of Thermal Deformation on Microstructure of Mg-9Zn-2Gd-1Y Alloy

对不同冷却速率的铸态Mg-9Zn-2Gd-1Y镁合金进行了恒温恒定压缩速率的热模拟压缩试验,并对样品进行了XRD物相分析以及金相和扫描电子显微(SEM)观察。结果表明合金中的第二相为脆性相,在压缩过程中会被破碎,而快速冷却的合金在压缩变形过程中会形成非均匀变形带,导致组织变形不均匀,原有的层片状共晶第二相被变形带破碎为亚微米尺度的颗粒。分析表明该合金的枝晶和共晶结构容易导致非均匀变形。

The as-cast Mg-9Zn-2Gd-1Y alloys prepared by different cooling speeds were compressed by hot compression simulationprocess.The specimens were investigated by optical micrograph,scanning electron microscope and X-ray diffraction.The results showthat the second phase was mainly quasi-crystal phase,which was very brittle,which was crashed during compressing.It showed thatdendritic crystal and eutectic structure of alloy would cause heterogeneous deformation.