挤压态稀土镁合金高温单轴拉伸行为特征研究

Research on High Temperature Uniaxial Tensile Behavior of As-Extruded Rare Earth Magnesium Alloy

使用Instron3382电子拉伸试验机研究了挤压态Mg-Gd-Y-Zn-Zr稀土镁合金的高温拉伸变形行为,分析并归纳了该合金在温度为250~350℃,应变速率为10-2~10-4 s-1条件下的峰值应力随温度和应变速率的变化关系.研究结果表明:温度和应变速率是影响高温变形力学性能的重要因素,随着温度的升高和应变速率的降低,峰值应力减小;随着变形温度的升高,应变速率敏感性增加,应力指数减小,其平均值为6.75;在试验温度范围内,随着温度的升高和应变速率的增加,变形激活能降低,位错的攀移和滑移为塑性变形的主要机制.

The high temperature tensile deformation behavior of the as-extruded Mg-Gd-Y-Zn-Zr magnesium alloy was studied using Instron3382 electronic tensile testing machine,and the relationship of the peak stress with temperature and strain rate at the strain rates of 10-2~10-4 s-1 and deformation temperatures of 250~350℃was analyzed and summarized.The results show that temperature and strain rate are important factors influencing mechanical properties of high temperature deformation,and the peak stress decreases with the increase of temperature and the decrease of strain rate.With the increase of deformation temperature,the sensitivity of strain rate increases,and the stress exponent n decreases.The average value of n is 6.75.In the range of test temperature,with the increase of temperature and strain rate,deformation activation energy decreases,and dislocation climbing and sliding become the main mechanisms of plastic deformation.