半固态AZ91镁合金固相线以下流变行为  

Rheological Behavior of Semi-solid AZ91 Magnesium Alloy Below Solidus

作　　者：姜龙 郑小平 宋进英 田亚强 陈连生 JIANG Long;ZHENG Xiaoping;SONG Jinying;TIAN Yaqiang;CHEN Liansheng(College of Metallurgy and Energy,North China University of Science and Technology,Tangshan 063210,China)

机构地区：[1]华北理工大学冶金与能源学院,河北唐山063210

出　　处：《热加工工艺》2023年第23期123-127,共5页Hot Working Technology

基　　金：国家自然科学基金项目(51474091,51574107);河北省自然科学基金项目(E2017209121);河北省高等学校科学技术研究项目(ZD2018242)。

摘　　要：采用Gleeble-3500热模拟实验机对冷轧与半固态热处理后的AZ91镁合金半固态坯料进行热压缩行为研究。所采用的工艺为应变速率0.001~10·s^(-1)温度300~450℃。基于对不同变形条件下试样的真应力-真应变曲线的分析,并通过Zener-Hollomom等参数的数值计算,建立了该材料的高温压缩本构方程。结果表明:半固态AZ91镁合金坯料的真应力-真应变曲线属于单峰动态再结晶型;流变应力随变形温度的升高而降低。应力峰值随变形温度的升高朝应变减小的方向移动。半固态AZ91热模拟压缩流变应力本构方程为:ε=2.01×10^(24)[sinh(0.2682σ)]^(7.605268)exp(-248140/RT)。在固相线下的高温压缩变形,除应变速率为0.01·s^(-1)、温度300、350、400℃或应变速率0.1·s^(-1)、温度300℃外,AZ91半固态坯料峰值应力均低于铸态AZ91镁合金的。The hot compressive behaviors of cold rolling and semi-solid heat treatment AZ91 magnesium alloy was studied on Gleeble-3500 thermal simulation machine.The adopted deformation temperature is 300-450℃,and strain rate is 0.001-10·s^(-1).The hot compressive constitutive model of the materia was established based on the analysis of stress-strain curves under different deformation condition and Zener-Hollomom calculation.The results show that the true stress-true strain curve of semi-solid AZ91 magnesium alloy is single peak dynamic recrystallization.The rheological stress decreases with the increase of deformation temperature.The stress peak moves coupling with the increase of deformation temperature in the direction of strain reduction.The constitutive equation of the compressive rheological stress of semi-solid AZ91 isε=2.01×10^(24)[sinh(0.2682σ)]^(7.605268)exp(-248140 RT).The stress peak of semi-solid AZ91 billet is lower than that of the cast AZ91 magnesium alloy,except in the conditions of strain rate of 0.01·s^(-1)and temperature of 300℃,350℃,400℃,or strain rate of 0.1·s^(-1)and temperatures of 300℃.

关 键 词：AZ91镁合金 半固态坯料 热压缩变形 流变应力 本构方程 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG166.4[金属学及工艺—金属材料]