7050铝合金高温变形过程中的微观组织特征  

Microstructure Characterization of 7050 Aluminum Alloy During High Temperature Deformation

作　　者：胡会娥[1] 孔小东[1] 陈德斌[1] 胡裕龙[1] 

机构地区：[1]海军工程大学化学与材料系,武汉430033

出　　处：《材料工程》2010年第11期52-56,共5页Journal of Materials Engineering

基　　金：材料成形与模具技术国家重点实验室资助项目(09-08)

摘　　要：研究了7050铝合金在温度为460℃,应变速率分别为1.0×10-4s-1和0.1s-1条件下的高温拉伸变形过程。结果表明:7050铝合金在高温拉伸过程中平均晶界取向差角与真应变之间保持比例关系,晶粒尺寸随变形的进行而增加。晶粒的长径比在变形条件为460℃/1.0×10-4s-1变形时基本保持不变;而变形条件为460℃/0.1s-1时,晶粒长径比则随着变形的进行而增加。微观组织结果表明,7050铝合金在460℃/1.0×10-4s-1的变形过程中,软化机制为连续动态再结晶,而变形条件为460℃/0.1s-1时,软化机制为动态回复。连续动态再结晶过程中平均晶界取向差角的持续增加与亚晶界的迁移和变形过程中晶界吸入位错有关。Dynamic recrystallization and dynamic recovery in 7050 aluminum alloy during high temperature deformation have been investigated by tensile tests conducted at 460℃ and strain rates of 1.0×10-4s-1 and 0.1s-1.It is shown that the increase in the average misorientation angle is proportional to the increase in the true strain during high temperature deformation of the 7050 aluminum alloy.The grain size of the 7050 aluminum alloy increases with increasing true strain with the strain rates of 1.0×10-4s-1 and 0.1s-1,respectively.While the aspect ratio of grains remains unchanged after high temperature deformation at 460℃/1.0×10-4s-1;and it increases with the true strain during deformation at 460℃/0.1s-1.Microstructure results show that continuous dynamic recrystallization and dynamic recovery are the softening mechanisms when strain rates are 1.0×10-4s-1 and 0.1s-1,respectively.The continuous increase of the average misorientation angle during continuous dynamic recrystallization is attributed to the migration of subgrain boundaries and the absorption of dislocations into grain boundaries.

关 键 词：铝合金 高温变形 软化机制 微观组织 

分 类 号：TG146.21[一般工业技术—材料科学与工程]