等通道转角挤压AZ61镁合金的塑性变形行为

Plastic deformation behavior of AZ61 magnesium alloy processed by equal channel angular pressing

为了确定等通道转角挤压对AZ61镁合金塑性变形能力的影响,针对经过二道次和不同路径等通道转角挤压的AZ61镁合金在不同试验温度和应变速率下进行了拉伸试验,并对相应的变形机制进行了分析.结果表明,在200～300℃之间,采用路径A和路径C等通道转角挤压的AZ61镁合金的伸长率随试验温度的升高而升高,而采用路径BC等通道转角挤压的AZ61镁合金的伸长率则随试验温度的升高而降低,其中经过路径BC等通道转角挤压的AZ61镁合金在200℃时伸长率可达272%,呈现出良好的低温超塑性;等通道转角挤压AZ61镁合金的塑性变形机制为晶界扩散控制的晶界滑移机制.

In order to identify the influence of equal channel angular pressing （ECAP） on the plastic deformation capacity of the AZ61 magnesium alloy, the tensile tests were conducted at different temperatures and strain rates for the AZ61 magnesium alloy subjected to two passes of ECAP with various routes. And the corresponding deformation mechanism was analyzed. The results show that in the testing temperature range from 200 to 300 ℃, with increasing the temperature, the elongation of the AZ61 alloy ECAPed with routes A and C increases, while that of the AZ61 alloy ECAPed with route Bc decreases. The elongation of the AZ61 alloy ECAPed with route Bc may reach 272% at 200 ℃. It means that the low temperature superplasticity has been achieved. It is suggested that the plastic deformation mechanism of the ECAPed AZ61 alloy is the grain-boundary sliding mechanism controlled by grain-boundary diffusion.