变形量和变形速率对AM60铸锭压缩过程中孪晶的影响

在电子万能试验机上对铸态AM60镁合金进行室温压缩试验，研究了在变形量分别为3．3％，10％，12％，20％，26％以及变形速率为0．2，0．5，2，5mm／min时压缩变形组织中孪晶的形态。结果表明：在塑性变形初期，只有少量晶粒内出现孪晶，孪晶较宽；而在变形末期，孪晶几乎分布于所有晶粒中，且出现了细而长的孪晶。随着变形速率的增大，孪晶变细，并且孪晶的密度增大，试样的屈服强度、抗压强度都升高。

Influence of Deformation Degree and Rate on Twins of Cast AM60 during Compression Test

Deformation twinning of cast magnesium alloy AM60 was investigated by compression at room temperature with various deformation degrees from 3. 3% to 24% and various deformation rates from 0. 2 mm/min to 5 mm/min, respectively. Microstructure of the deformed samples examined by optical microscopy showed that thick twins exited in a few amount of crystals at the beginning of the deformation. The thin-long twins and the thick twins appeared at the end of the deformation, and they could be observed in almost all crystals. With increasing compressing rates, the yield strength, compressive resistance fracture strength and density of twins increased, and twins became thin.