(北京有色金属研究总院 有色金属加工事业部,北京 100088)
摘 要: 在Gleeble−1500D热模拟机上采用等温压缩实验研究Zn-8Cu-0.3Ti锌合金的高温流变行为,获得锌合金在变形温度为230~380 ℃、应变速率为0.01~10 s−1和变形程度为50%条件下的真应力-应变曲线,根据动态材料模型(DMM)建立锌合金的热加工图。结果表明:Zn-8Cu-0.3Ti锌合金在实验条件下具有正的应变速率敏感性,流变应力随着应变速率的增大而增大,随着变形温度的升高而减小,该合金的流变应力行为可用Arrhenius方程来描述。在本研究条件下,Zn-8Cu-0.3Ti锌合金在热变形时存在一个失稳区,即应变速率0.2 s−1以上的区域;在应变速率小于0.001 s−1和340~370 ℃温度范围内,最大功率耗散系数为0.53,该安全区域内合金的变形机制为动态再结晶。
关键字: 锌合金;流变应力模型;高温变形;加工图
(Nonferrous Processing Division, General Research Institute for Nonferrous Metals, Beijing 100088, China)
Abstract:The hot compression deformation of Zn-8Cu-0.3Ti alloy was performed on Gleeble−1500D at temperature of 230−380 ℃, strain rate of 0.01−10 s−1, height direction reduction of 50%. The true stress-strain curves under different deformation conditions were obtained and the processing map was developed based on the dynamic material modeling (DMM). The results indicate that the flow stress is sensitive to the strain rate and the deforming temperature. The flow stress increases with increasing the strain rate, and decreases with increasing the deforming temperature, which can be described by a constitutive equation in the form of Arrhenius function. The processing map shows one unsteady zone of high temperature deformation of Zn-8Cu-0.3Ti alloy, which is above strain rate of 0.2 s−1. At the temperature of 340−370 ℃ and below the strain rate of 0.001 s−1, the peak efficiency of power dissipation is 0.53, in which zone the deformation mechanism is dynamics recrystallization (DR).
Key words: zinc alloy; flow stress model; high temperature deformation; processing map