热轧MB8镁合金的超塑性

Superplasticity of hot rolled MB8 magnesium alloy

对热轧MB8(Mg-1.5Mn-0.3Ce)镁合金板材的超塑性进行了研究。高温拉伸实验结果表明,合金在573～723 K及2×10-2～4×10-4s-1应变速率范围内具有良好的超塑性,在673 K及4×10-4s-1条件下得到最大断裂伸长率为441.6%;在723 K时最高应变速率敏感系数m为0.42,此时流变应力仅为6.3 MPa。此外,采用SEM对拉伸试样断口形貌进行了观察,并通过断裂区域显微组织的观察分析了Mg-1.5Mn-0.3Ce镁合金超塑性变形的机制。

Superplasticity of hot rolled MB8(Mg-1.5Mn-0.3Ce) magnesium alloy was studied.The results show that the alloy exhibits superplasticity at temperature of 573 to 723 K and strain rate of 2×10-2 to 4×10-4s-1.The maximum elongation to failure reaches 441.6% at 673 K and 4×10-4 s-1.At 723 K,the strain rate sensitivity and flow stress are 0.42 and 6.3 MPa,respectively.Moreover,the fracture morphology of the tensile specimens was observed by SEM,and the mechanism of the superplastic deformation was discussed based on the observation of microstructure near the fracture region after tensile test.