7075铝合金热变形行为和组织演变

doi:10.13251/j.issn.0254-6051.2023.06.027

摘要/Abstract

摘要： 利用MMS-100热/力模拟试验机对固溶态7075铝合金进行了热压缩试验, 构建了能描述合金在温度为350~450 ℃、应变速率为0.01~10 s^-1条件下流变应力规律的本构方程, 基于动态材料模型和显微组织确定了该合金热加工的最佳工艺窗口。结果表明, 475 ℃固溶温度下, MgZn₂相可全部回溶于基体, 随固溶时间延长, Al₂CuMg和Al₇Cu₂Fe回溶量增多;合金的流变应力随着温度的降低和应变速率的增加而增大, 热变形激活能Q=153.724 kJ/mol;功率耗散系数随温度的升高和应变速率的减小逐渐增大, 流变失稳区随应变的增大向高应变速率方向移动, 合金的热加工最佳工艺窗口为变形温度420~450 ℃, 应变速率0.01~0.02 s^-1。

关键词: 7075铝合金, 热变形, 本构方程, 热加工图, 组织演化

Abstract: Hot compression test was carried out for the as-solid solution treated 7075 aluminum alloy by MMS-100 thermo-mechanical simulator and the flow stress constitutive model of the alloy was constructed at 350-450 ℃ and strain rate among 0.01-10 s^-1. Based on the dynamic material model and microstructure, the optimum process window for the hot deformation was determined. The results show that after solution treatment at 475 ℃, the MgZn₂ phase is all dissolved back into the matrix, and with the increase of solution treatment time, the fraction of Al₂CuMg and Al₇Cu₂Fe dissolved in matrix increases. The flow stress of the alloy increases with the decrease of temperature and increase of strain rate, and the hot deformation activation energy calculated is approximately Q=153.724 kJ/mol. The power dissipation coefficient gradually increases with the temperature increasing and strain rate decreasing, the flow instability zones move to higher strain rate with the increase of strain, the optimum processing window of the alloy is deformation temperature of 420-450 ℃ and strain rate of 0.01-0.02 s^-1.

Key words: 7075 aluminum alloy, hot deformation, constitutive equation, processing map, microstructure evolution

中图分类号:

TG146.2⁺1

李琛, 王和斌, 欧平, 王航, 王俊峰, 张济山. 7075铝合金热变形行为和组织演变[J]. 金属热处理, 2023, 48(6): 147-156.

Li Chen, Wang Hebin, Ou Ping, Wang Hang, Wang Junfeng, Zhang Jishan. Hot deformation behavior and microstructure evolution of 7075 aluminum alloy[J]. Heat Treatment of Metals, 2023, 48(6): 147-156.

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