Hot deformation behavior and microstructural evolution of Al-Zn-Mg-0.25Sc-Zr alloy during compression at elevated temperatures  

Al-Zn-Mg-0.25Sc-Zr合金的热压缩变形行为和微观组织演化(英文)

作　　者：张志野[1] 潘清林[1,2] 周坚[1] 刘晓艳[1] 陈琴[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2012年第7期1556-1562,共7页中国有色金属学报（英文版）

基　　金：Project(2012CB619503)supported by the High-tech Research and Development Program of China

摘　　要：The hot deformation behavior of Al-Zn-Mg-0.25Sc-Zr alloy and its microstructural evolution were investigated by isothermal axisymmetric hot compression tests at temperatures from 340 to 500°C and strain rates ranging from 0.001 to 10 s -1 .The steady flow stress increased with increasing the strain rate or decreasing the deformation temperature,which can be described by a hyperbolic-sine constitutive equation with the deformation activation energy of 150.25 kJ/mol.The tendency of dynamic recrystallization enhanced at high deforming temperatures and low strain rates,which corresponded to low Z values.With decreasing Z value,the main softening mechanism of the alloy transformed from dynamic recovery to dynamic recrystallization, correspondingly,the subgrain size increased and the dislocation density decreased.采用等温轴对称热压缩实验对Al-Zn-Mg-0.25Sc-Zr合金的热变形行为和微观组织演化进行研究。变形温度为340~500°C,应变速率为0.001~10s-1。结果表明：稳态流变应力随着应变速率的增加和变形温度的降低而增大,该合金的流变应力行为可用双曲正弦形式的本构方程来描述,其变形激活能为150.25kJ/mol。在变形温度较高和应变速率较低（即Z参数较低）的条件下,动态再结晶更容易发生。随着Z参数的变小,合金的主要软化机制由动态回复转变为动态再结晶,合金中的位错密度降低,亚晶尺寸增大。

关 键 词：Al-Zn-Mg-Sc-Zr alloy hot deformation flow behavior microstructural evolution 

分 类 号：TG146.21[一般工业技术—材料科学与工程]