摘要
在Gleeble3500热模拟试验机上通过单道次热压缩实验,研究了7A55铝合金热变形过程中的高温流变行为,构建了热加工图。利用光学显微镜和透射电镜表征观测了变形后的微观组织演变规律。实验结果表明:7A55铝合金在热变形过程中具有动态软化趋势,应变速率敏感性高。随应变速率的增加,峰值应力和应变均提高;随变形温度的提高,峰值应力和应变均减小。在400~450℃温度区间,应变速率在0.01 s-1左右时,功率耗散效率均在35%以上,具有最优的热加工性。在较高的温度和较低的应变速率下易发生动态再结晶行为。较低温度和较高的应变速率缩短了变形时间,限制了位错的运动,抑制了动态回复和动态再结晶的进行。
The single pass thermal compression tests of 7A55 aluminum alloy were studied by using Gleeble3500 thermal simulation ma-chine.The hot deformation behavior was investigated,and the processing map was established.The microstructure evolution law after de-formation was characterized by using OM and TEM.The exprimental results indicate that 7A55 aluminum alloy has dynamic softening trend and high strain rate sensitivity during isothermal compression process.Peak stress and peak strain increase with the increasing of strain rate,while decrease with increasing of temperature.The power dissipation efficiency values are higher than 35%under temperature range of 400-450℃and strain rate of 0.01 s-1,which has the best hot workability.High temperature and low strain rate are better for the occurrence of dynamic recrystallization,the low temperature and high strain rate shorten the deformation time,constrain the movement of dislocation and inhibit the dynamic recovery and recrystallization.
作者
张秋道
朱海琴
李辉
ZHANG Qiu-dao;ZHU Hai-qin;LI Hui(Scientific Research Office,Yantai Nanshan University,Yantai 265713,China;National Engineering Research Center for Plastic Working of Aluminum Alloys,Shandong Nanshan Aluminum Co.,Ltd.,Yantai 265700,China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2019年第4期182-186,共5页
Journal of Plasticity Engineering
基金
山东省高校科技计划资助项目(J18KA028)
烟台重点研发计划资助项目(2017ZH081)
关键词
7A55铝合金
热变形行为
热加工图
组织演变
7A55 aluminum alloy
hot deformation behavior
processing map
microstructure evolution