变形速率对7075铝合金流变应力的影响

Effect of strain rates on flow stress feature of 7075 aluminum alloy

采用Gleeble-1500热模拟机对7075铝合金触变高温压缩变形过程中的变形特性进行研究,分析该合金的应变速率与流变应力之间的关系,采用线性回归法建立了流变模型。结果表明:保温时间1min、变形温度350～450℃、应变速率0.01～1.00s-1的条件下,应力曲线变化可分为加工硬化段、平稳变化段和稳定变化段三个阶段。随着应变速率的增加,稳态流变应力增大;应变速率和流变应力之间基本满足指数关系,该合金高温塑性变形过程是一种高温蠕变的热激活过程。

The flow stress feature of 7075 aluminum alloy, during high temperature plastic deformation ranging from 300-500 ℃ and strain rates of 0.01-1,00 s^-1, was studied by the thermal compression using Gleeble-1500 hot-simulator, The results show that strain rates control the flow stress. The flow stress increases with the increase of strain rates. A high temperature relationship is found to correlate well the flow stress with the strain rate.