不同温度下AM80镁合金的动态力学响应及本构建模  

Dynamic Mechanical Response and Constitutive Modeling of AM80 Magnesium Alloy at Various Temperatures

作　　者：陈斐洋 郭鹏程 胡泽豪[1] 马洪浩[1] 张立强 CHEN Feiyang;GUO Pengcheng;HU Zehao;MA Honghao;ZHANG Liqiang(College of Mechanical and Electrical Engineering,Central South University of Forestry and Technology,Changsha 410004,China;State Key Laboratory of Advanced Design and Manufacture for Vehicle Body,Hunan University,Changsha 410082,China)

机构地区：[1]中南林业科技大学机电工程学院,长沙410004 [2]湖南大学汽车车身先进设计制造国家重点实验室,长沙410082

出　　处：《材料导报》2021年第16期16093-16098,共6页Materials Reports

基　　金：国家自然科学基金(51905166);湖南省自然科学基金资助项目(2019JJ50586);湖南省教育厅科学研究项目(18B193)。

摘　　要：为构建可准确预测镁合金动态力学响应的统一本构模型,采用分离式霍普金森压杆装置对AM80镁合金进行高速冲击实验,变形温度为298 K、423 K和523 K,应变速率为1100~5000 s^(-1)。结果表明:AM80镁合金具有明显的应变速率敏感性。变形温度为298 K时,镁合金的流变应力表现为正应变速率敏感性,当应变速率增至5000 s^(-1)的变形后期,镁合金的流变应力则表现为负应变速率敏感性;变形温度为423 K和523 K时,镁合金的流变应力表现为正应变速率敏感性,当应变速率高于临界值时,镁合金的流变应力则表现为负应变速率敏感性。将应变速率强化参数C和应变硬化参数n修正为变形温度T的函数,优化了Johnson-Cook本构模型,本构拟合结果与实验结果的误差在±10%范围内,其相关系数(R)和平均相对误差(AARE)分别为0.987、3.88%,说明所建本构模型能够准确预测AM80镁合金在不同变形条件下的流变应力行为。In order to built a constitutive model which can accurately predict the dynamic mechanical response of magnesium alloys,high-speed impact tests were carried out with AM80 alloy using a separate Hopkinson pressure bar.The deformation temperatures were 298 K,423 K and 523 K,and the applied strain rate ranges from 1100 s^(-1) to 5000 s^(-1).At 298 K,the flow stress of magnesium alloy exhibits a positive strain rate sensiti-vity(SRS),followed by a negative SRS as the strain rate increases to 5000 s^(-1) in the later deformation stage.At 423 K and 523 K,the flow stress of magnesium alloy first shows a positive SRS,and then illustrates a negative SRS as the strain rate is higher than their critical values.An optimized Johnson-Cook constitutive model is built by modifying the strain rate strengthening parameter C and strain hardening parameter n to a function of deformation temperature T.The errors between the constitutive fitting and experiment results are within the range of-10%—10%,and the correlation coefficient R and average absolute relative error(AARE)are 0.987 and 3.88%,respectively.These shows that the optimized constitutive can accurately predict the high-speed impact flow stress behavior of AM80 alloy under various deformation temperatures.

关 键 词：AM80镁合金 变形温度 动态力学响应 本构建模 

分 类 号：TP182[自动化与计算机技术—控制理论与控制工程]