铸态AZ31B镁合金高温变形行为数学建模  

Mathematical modeling about as-cast AZ31B magnesium alloy deformation under high temperature

作　　者：马立峰[1] 贾伟涛[1,2] 黄志权 林金宝[1] MA Lifeng;JIA Weitao;HUANG Zhiquan;LIN Jinbao(Heavy Machinery Engineering Research Center, Ministry of Education,Taiyuan University of Science and Technology, Taiyuan 030024, China;Key Laboratory of Electromagnetic Processing of Materials, Ministry of Education,Northeastern University, Shenyang 110819, China)

机构地区：[1]太原科技大学重型机械教育部工程研究中心,山西太原030024 [2]东北大学材料电磁过程研究教育部重点实验室,辽宁沈阳110819

出　　处：《中南大学学报（自然科学版）》2017年第12期3193-3199,共7页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51105264);山西省高校青年学术带头人计划项目(TYAL);山西省科技攻关项目(20130321010-03)~~

摘　　要：采用Gleeble-1500热/力模拟试验机对铸态AZ31B镁合金圆柱试样进行轴向热压缩试验,并基于动态材料模型计算应变ε为0.4时的热加工图,研究镁合金热变形行为,以建立AZ31B镁合金真实应力与应变、温度及应变速率间的构效关系。研究结果表明:镁合金的变形激活能关于温度呈高度非均匀性分布,在整体范围内对该参数进行平均估算的方法导致Arrhennius本构方程产生较大拟合误差;将523~723 K变形温度分解为523~573,573~623和623~723 K来分别建立Arrhennius本构方程,可有效提高该方程对峰值应力的预测精度;结合优化后的Sellars和Arrhennius模型,采用常用数学方程构建的热变形抗力模型能准确表征AZ31B镁合金在523~723 K及0.005~5.000 s^(-1)范围内的热变形行为。The as-cast AZ31B magnesium alloy cylindrical samples were compressed uniaxially by employing the Gleeble?1500thermo-mechanical simulator.Using the dynamic material model,thermal processing diagram under the condition ofε=0.4was calculated to study the thermal deformation behavior of AZ31B and further establish the structure-activity relationship between the true stress,strain,temperature and strain rate.The results show that the activation energy for hot deformation has a high nonuniform distribution over temperature.The average estimation for activation energy within the whole scope leads to larger fitting error of the Arrhennius constitutive equation.Decomposition of deformation temperature of523?723K into523?573K,573?623K and623?723K to establish the Arrhennius constitutive equation respectively can effectively improve the prediction accuracy of peak stress.The new hot compression deformation resistance model,which is established on the basis of the improved Sellars and Arrhennius models using simple and common mathematical equations,can accurately characterize the thermal deformation behaviors of AZ31B in the range of523?723K and0.005?5.000s?1.

关 键 词：热加工图 峰值应力 变形抗力 

分 类 号：TG146.2[一般工业技术—材料科学与工程]