AA6014铝合金热变形行为及热加工图

Hot deformation behavior and hot processing map of AA6014 aluminum alloy

采用热压缩模拟实验研究了 AA6014铝合金在变形温度为320~520℃,应变速率为0.01~10 s^(-1)下的热变形行为。研究结果表明,在变形温度和应变速率的变化过程中,AA6014铝合金的应力呈温度负敏感性和应变速率正敏感性,增大应变速率和降低变形温度均会增大合金的变形抗力,应力-应变曲线为动态回复型曲线。依据应变量为0.3、0.5、0.7和0.9时材料的热变形数据,基于DMM原理构建了不同应变量下的AA6014铝合金热加工图,分析和讨论了 AA6014铝合金的变形工艺。结果表明,AA6014铝合金的安全热加工区间集中于中、低应变速率区,在安全区内存在动态回复及再结晶特征,失稳区内出现局部流变特征。其功率耗散率η最大值位于320 ℃<T<520 ℃,0.56 s^(-1)<■<1 s^(-1)变形条件范围内,AA6014铝合金的最佳成形工艺窗口确定为370℃<T<520℃,0.01 s^(-1)<■<0.056 s^(-1)和320℃<T<520℃,0.56 s^(-1)<■<1 s^(-1)。

The hot deformation behavior of AA6014 aluminum alloy at the deformation temperature of 320-520℃and the strain rate of0.01-10 s^(-1) was studied using hot compression simulation experiments.The research results show that during the changing process of deformation temperature and deformation rate,the stress of AA6014 aluminum alloy has negative temperature sensitivity and positive rate sensitivity.Increasing the strain rate and decreasing the deformation temperature can increase the deformation resistance of alloy.The stress-strain curve is dynamic recovery curves.According to the thermal deformation data at strain of 0.3,0.5,0.7 and 0.9,the hot processing maps of AA6014 aluminum alloy with different strains were established based on the DMM principle.The deformation process of AA6014 aluminum alloy was analyzed and discussed.The results show that the safe hot working interval of AA6014 aluminum alloy is concentrated in the medium and low strain rate areas.The dynamic recovery and recrystallization characteristics exist in the safe areas and local rheological characteristics exist in the unstable area.The maximum value of the power dissipation rate η locates in the deformation condition range of 320 ℃<T<520 ℃,0.56 s^(-1)<■<1 s^(-1).The optimal forming process window of AA6014 aluminum alloy is determined as 370℃<T<520℃,0.01 s^(-1)<■<0.056 s^(-1) and 320℃<T<520℃,0.56 s^(-1)<■<1 s^(-1)