均质态7475铝合金的热变形行为  

Thermal deformation behavior of homogeneous 7475 aluminum alloy

作　　者：王永红 王经涛 黄同瑊 杨航 郭丰佳 郑铖 Wang Yonghong;Wang Jingtao;Huang Tongjian;Yang Hang;Guo Fengjia;Zheng Cheng(National Engineering Research Center for Plastic Working of Aluminium Alloys,Shandong Nanshan Aluminium Co.,Ltd.,Longkou 265713,China;Nonferrous Metal Industry Research Institute,Shandong Nanshan Aluminum Co.,Ltd.,Longkou 265713,China;College of Materials Science and Engineering,Yantai Nanshan University,Longkou 265713,China)

机构地区：[1]山东南山铝业股份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265713 [2]山东南山铝业股份有限公司有色金属产业研究院,山东龙口265713 [3]烟台南山学院材料科学与工程学院,山东龙口265713

出　　处：《锻压技术》2024年第10期248-255,共8页Forging & Stamping Technology

摘　　要：利用Gleeble-3500热模拟试验机研究了均质态7475铝合金在变形温度为300~450℃、应变速率为0.01~1s^(-1)下的高温热变形行为。结果表明,随着应变速率的增大和变形温度的降低,流变应力呈增大趋势,真应力-真应变曲线表现出明显的加工硬化和动态软化现象,并依此建立了基于双曲正弦方程的本构模型以描述合金在高温下的热变形行为。此外,基于试验数据和动态材料模型,构建了不同应变下的热加工图,揭示了应变、变形温度和应变速率对功率耗散率η和流变失稳ξ的影响;根据整个热变形过程中功率耗散率值的变化趋势,得出均质态7475铝合金主要经历了动态回复和动态再结晶,未发生超塑性;进一步对流变失稳区和安全加工区域进行分析,确定均质态7475铝合金最佳的热加工区域为变形温度为420~450℃和应变速率为0.026~0.185s^(-1)。The high-temperature thermal deformation behavior of homogeneous 7475 aluminum alloy was studied by using thermal simula-tion testing machine Gleeble-3500 at the deformation temperature of 300-450℃and the strain rate of 0.01-1 s^(-1).The results show that with the increasing of strain rate and the decreasing of deformation temperature,the rheological stress shows an increasing trend,and the true stress-true strain curve exhibits obvious work hardening and dynamic softening phenomena.Based on this,a constitutive model based on hyperbolic sine equation is established to describe the thermal deformation behavior of alloy at high temperature.In addition,based on the experimental data and the dynamic material model,the thermal processing maps under different strains are established to reveal the in-fluences of strain,deformation temperature and strain rate on the power dissipation rate η and rheological instabilityξ.According to the trend of power dissipation rate during the entire thermal deformation process,it is concluded that the homogeneous 7475 aluminum alloy mainly undergoes dynamic recovery and dynamic recrystallization,without superplasticity.The rheological instability zone and safe pro-cessing zone are further analyzed,and the optimal thermal processing zone of homogeneous 7475 aluminum alloy is determined to be the deformation temperature of 420-450℃and the strain rate of 0.026-0.185 s^(-1).

关 键 词：均质态7475铝合金 热变形 流变应力 本构方程 热加工图 

分 类 号：TG146.21[一般工业技术—材料科学与工程]