均质态7075铝合金热压缩流变行为及微观组织研究  

Study on hot compression rheological behavior and microstructure of homogeneous 7075 aluminum alloy

作　　者：杨鑫 孙有政 曹善鹏 王莹宁 汲庆涛 赵忠超 王玉玲 YANG Xin;SUN You-zheng;CAO Shan-peng;WANG Ying-ning;Ji Qing-tao;ZHAO Zhong-chao;WANG Yu-ling(National Aluminum Alloy Pressure Processing Engineering Technology Research Center,Shandong Nanshan Aluminum Industry Co.,Ltd.,Longkou 265700,China;Shandong Aluminum Alloy Pressure Processing Technology Innovation Center,Shandong Nanshan Institute of Science and Technology Co.,Ltd.,Longkou 265700,China;College of Materials Science and Engineering,Yantai Nanshan University,Longkou 265700,China)

机构地区：[1]山东南山铝业有限公司国家铝合金压力加工工程技术研究中心,山东龙口265700 [2]山东南山科学技术研究院有限公司山东省铝合金压力加工技术创新中心,山东龙口265700 [3]烟台南山学院材料科学与工程学院,山东龙口265700

出　　处：《塑性工程学报》2024年第10期184-197,共14页Journal of Plasticity Engineering

基　　金：山东省高等学校“青创科技支持计划”(2021KJ089)。

摘　　要：为研究均质化7075铝合金的热变形行为,对铸态7075铝合金进行均匀化热处理,采用Gleeble-3500热模拟试验机对均质态7075铝合金进行等温单轴压缩试验,获得了压缩温度为310~400℃、应变速率为0.01~10 s^(-1)的真应力-真应变曲线,研究热压缩过程中的流变行为。并基于Arrhenius方程和Zener-Hollomon参数构建7075铝合金应变补偿型本构方程,由方程得到的流变应力与试验结果拟合度较高,决定系数为0.9949,表明该本构方程对均质化7075铝合金热变形行为具有较高的预测精度。根据真应力-真应变曲线绘制不同应变条件下的功率耗散图和失稳图,结果表明,在370~400℃/0.1~1 s^(-1)范围内功率耗散效率较高,7075铝合金能够稳定发生应变。在热压缩过程中,无取向的自由晶粒向着Goss织构转变。随着压缩应变速率的增加,材料内部的位错密度、小角度晶界占比和织构强度增加。含Cr相对位错运动有钉扎作用,在低温高应变速率的变形过程中会发生位错缠结,而在高温低应变速率时,第二相的钉扎效应减弱,容易发生再结晶。To study the hot deformation behavior of homogenized 7075 aluminum alloy,the as-cast 7075 aluminum alloy was homogenized by heat treatment.The isothermal uniaxial compression tests of the homogeneous 7075 aluminum alloy were carried out by Gleeble-3500 thermal simulator.The true stress-true strain curves at the temperature range of 310-400℃and the strain rate of 0.01-10 s^(-1)were obtained to study the rheological behavior during hot compression.Based on the Arrhenius equation and Zener-Hollomon parameters,the strain-compensated constitutive equation of 7075 aluminum alloy was established.The flow stress obtained from the equation is in good agreement with the experimental result,and the determination coefficient is 0.9949,indicating that the constitutive equation has high prediction accuracy for the hot deformation behavior of homogeneous 7075 aluminum alloy.According to the true stress-true strain curves,the power dissipation diagram and instability diagram under different strain conditions were drawn.The results show that the power dissipation efficiency is higher in the range of 370-400℃and 0.1-1 s^(-1),and 7075 aluminum alloy can be strained stably.During hot compression,the unoriented free grains transform to the Goss texture.With the increase of compressive strain rate,the dislocation density,the percent-age of low-angle grain boundaries and the texture intensity increase.The relative dislocation motion with Cr has a pinning effect,and dis-location entanglement occurs during deformation at low temperature and high strain rate,while at high temperature and low strain rate,the pinning effect of the second phase is weakened,and recrystallization is easy to occur.

关 键 词：7075铝合金 流变应力 本构方程 热变形 

分 类 号：TG146.21[一般工业技术—材料科学与工程]