7A85航空铝合金热加工过程的本构变形行为及组织演变  

Constitutive deformation behavior and microstructure evolution of 7A85 aerospace aluminum alloy during hot forming process

作　　者：高岩[1,2] 丛大鹏 于春鹏 陈丽丽[1] GAO Yan;CONG Da-peng;YU Chun-peng;CHEN Li-li(Institute of Science and Technology,Yantai Nanshan University,Yantai 265713,China;National Engineering Research Center for Plastic Working of Aluminum Alloys,Shandong Nanshan Aluminum Co.,Ltd.,Yantai 265700,China;Yantai Engineering&Technology College,Yantai 265700,China)

机构地区：[1]烟台南山学院科学技术研究院,山东烟台265713 [2]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,山东烟台265700 [3]烟台工程职业技术学院,山东烟台265700

出　　处：《塑性工程学报》2019年第5期225-231,共7页Journal of Plasticity Engineering

基　　金：山东省高校科技计划(J18KA028);烟台市重点研发计划(2017ZH081)

摘　　要：利用热模拟试验机研究了7A85铝合金的热变形行为,表征了不同热加工制度下的微观组织。结果表明7A85铝合金在热变形过程中具有稳态流变特征。变形过程中应力呈现正的应变速率敏感性和负的温度敏感性。变形温度越高,应变速率效应越明显。350℃热变形温度下,7A85铝合金基体同时存在高位错密度晶粒和再结晶晶粒。晶界弓出形核是7A85铝合金在热变形过程中动态再结晶的有效机制,位错密度梯度形成的能量差是晶界迁移的驱动力。7A85铝合金的热压缩变形过程为热激活过程,激活能达到153.88 kJ·mol^-1。Z参数随应变速率的增加和变形温度的降低而降低,可较好的描述铝合金的热变形过程。The hot deformation behavior of 7 A85 aluminum alloy was investigated by thermal simulation machine,the microstructure after different hot compression processes was characterized. The results indicate that 7 A85 aluminum has steady rheological characteristic during the hot deformation process. The stress shows positive strain rate sensitivity and negative temperature sensitivity during the deformation process. The higher the deformation temperature is,the more obvious the strain rate effect is. Under the deformation temperature of 350℃,the grains with high density dislocation coexist with recrystalliztaion grains in the matrix of 7 A85 aluminum alloy. The nucleation mechanism of grain boundary bow-out is the effective mechanism in dynamic recrystallization,and the energy difference caused by gradient of dislocation density is the driving force of grain boundary migration. The hot compression process of 7 A85 aluminum alloy is a thermally activated process and has an activation energy of 153. 88 kJ·mol-1. Z parameter decreases with the increase of strain rate and the decrease of temperature,which can depict the hot deformation of aluminum alloy well.

关 键 词：航空铝合金 热变形行为 本构方程 微观组织演变 

分 类 号：TG111.7[金属学及工艺—物理冶金]