摘要
研究了7A85铝合金在应变速率为0.001~1 s-1、变形温度为250~450℃条件下热压缩变形过程中的微观组织演变规律。结果表明,7A85铝合金在低温条件下主要发生动态回复,高温条件下主要发生动态再结晶。在动态再结晶过程中,连续动态再结晶和非连续动态再结晶现象同时存在,350~400℃是动态回复向动态再结晶的转变温度区间。7A85铝合金组织演变对于温度的敏感性较高,随着温度的升高,平均取向差角θc显著增加,增加范围为0.93°~7.13°。350℃变形温度下的小角度晶界比例fLAGBs较400℃时有所提高,最高增幅为27.9%。在450℃变形温度下,应变速率对材料再结晶行为的影响显著,再结晶晶粒随着应变速率降低发生了明显长大。最后,采用线性回归方法建立了450℃变形温度条件下7A85铝合金的动态再结晶晶粒尺寸演化模型。
The microstructure evolution rule of 7A85 aluminum alloy during hot compression deformation process was studied at strain rate of 0.001-1 s-1 and deformation temperature of 250-450℃.The results show that for 7A85 aluminum alloy,the dynamic recovery(DRV)is the main mechanism at low temperature,while the dynamic recrystallization(DRX)is the main mechanism at high temperature.Both continuous dynamic recrystallization(CDRX)and discontinuous dynamic recrystallization(DDRX)phenomenon exist during DRX.350-400℃is the transformation temperature interval from dynamic recovery to dynamic recrystallization.The sensitivity of microstructure evolution to temperature of 7A85 aluminum alloy is relatively high.The mean misorientation angleθc increases significantly with the increase of temperature and the increasing range is 0.93°-7.13°.The proportion of grain boundary with small angle fLAGBS at 350℃is higher than that at 400℃,and the maximum increase is 27.9%.The effect of strain rate on recrystallization behavior is significant at the deformation temperature of 450℃,and the recrystallization grains grow up obviously with the decrease of strain rate.Finally,the grain size evolution model of 7A85 aluminum alloy dynamic recrystallization at the deformation temperature of 450℃was established by linear regression method.
作者
焦子腾
胡建良
金淼
王欢
JIAO Zi-teng;HU Jian-liang;JIN Miao;WANG Huan(School of Mechanical Engineering,Yanshan University,Qinhuangdao 066004,China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2020年第3期137-145,共9页
Journal of Plasticity Engineering
基金
国家自然科学基金资助项目(51401179,51675465)
河北省自然科学基金资助项目(E2015203116,E2019203075)
河北省教育厅青年拔尖人才计划项目(BJ2019001)
高性能复杂制造国家重点实验室开放课题(Kfkt2017-07)
燕山大学博士基金资助项目。
关键词
7A85铝合金
热变形
微观组织演变
动态再结晶
7A85 aluminum alloy
hot deformation
microstructure evolution
dynamic recrystallization
