AZ31B镁合金热拉伸流变应力研究

Study on flow stress of AZ31B magnesium alloy at elevated temperature

针对不同加工方法制备的AZ31B镁合金薄板,利用热拉伸试验机和金相显微镜对其在不同温度和变形速率下的流变应力进行了实验研究。结果表明,变形温度和变形速率对热拉伸时镁合金的流变应力有显著影响,峰值流变应力随应变速率的降低和变形温度的升高而降低。峰值流变应力随板材的厚度增加而发生变化,低温时厚度效应较为明显。退火处理对冷轧板的峰值流变应力影响较小,冷轧板可直接用于热加工成形。峰值流变应力变化规律:挤压板>热轧板>冷轧板。

Flow stress of different temperatures and deformation rate on AZ31B magnesium alloy sheets of different preparation method was studied by tensile test machine and metalloscope. The results showed the effects of deformation temperature and deformation rate on flow stress of hot tensile test of magnesium alloy was remarkable. Peak flow stress was reduced with strain rate decrease and deformation temperature increase. Peak flow stress was changed with the sheets thickness increase, and thickness effect was remarkable at low temperature. The effect of annealing on peak flow stress of cold rolled sheet was little. Cold rolled sheet could be hot formed directly. The change rule of peak flow stress： extrusion sheet〉hot rolled sheet〉cold rolled sheet.