摘要
研究了一种新型快速时效响应7A75铝合金的热变形本构模型及其热变形过程中的微观组织演变规律。通过Gleeble-3500热模拟试验机进行了单道次热压缩实验,利用金相显微镜和透射电镜观察进行了合金的微观组织表征。结果表明,铸态7A75铝合金的平均晶粒尺寸约为165μm,均匀化处理后,基体平均晶粒尺寸约为220μm。同一变形温度下,流变应力随应变速率的增大而增大;同一应变速率下,流变应力随变形温度的增加而降低。由构建的全应变本构模型获得的流变应力预测值与实验值的相关系数为0.993,相对误差为2.85%,一致性良好。高的应变速率和低的变形温度抑制了再结晶的发生和再结晶晶粒的长大。在应变速率为0.01 s^-1,变形温度为390和430℃时,通过形变诱导析出机制,析出部分尺寸为100~200 nm的第二相粒子,有效地钉扎了晶界。
The hot deformation constitutive model and microstructue evolution laws during hot deformation process of a novel quick bake hardening response 7 A75 aluminum alloy were studied.The single pass hot compression test was conducted using Gleeble-3500 thermal simulator.The microstructure of the alloy was observed and characterized by optical microscopy(OM)and transmission electron microscopy(TEM).The results show that the average grain size of the as-cast 7 A75 aluminum alloy is about 165μm,and after the homogenization treatment,the average grain size of matrix is about 220μm.The flow stress increases with the increase of strain rate at the same deformation temperature,and decreases with the increase of deformation temperature at the same strain rate.The correlation coefficient between the predicted values of flow stress obtained by the established full strain constitutive model with the experimental values is 0.993,and the relative error is 2.85%,which indicates good consistency.High strain rate and low deformation temperature inhibit the occurrence of recrystallization and the growth of recrystallization grains.When the strain rate is 0.01 s^-1 and the deformation temperature is 390 and430℃,some second phases with size of 100-200 nm precipitate through the deformation induced precipitation mechanism,which pin the grain boundary effectively.
作者
宗海明
孔德斌
郝鑫弟
王军庆
李辉
王家毅
ZONG Hai-ming;KONG De-bin;HAO Xin-di;WANG Jun-qing;LI Hui;WANG Jia-yi(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
2020年第9期153-160,共8页
Journal of Plasticity Engineering
基金
山东省重点研发计划项目(2019GGX102025)
山东省高等学校青创科技计划(2019KJA019)。
关键词
7A75铝合金
本构模型
微观组织
热变形
7A75 aluminum alloy
constitutive model
microstructure
hot deformation
