不同加载路径下挤压WE43镁合金的高速冲击力学响应及本构模型  

Mechanical Responses and Constitutive Modeling of an Extruded WE43 Magnesium Alloy Under High-speed Impact with Different Loading Paths

作　　者：叶拓 邱飒蔚 夏二立 郭鹏程 吴远志[1] 李落星[2,3] YE Tuo;QIU Sawei;XIA Erli;GUO Pengcheng;WU Yuanzhi;LI Luoxing(School of Intelligent Manufacturing and Mechanical Engineering,Hunan Institute of Technology,Hengyang 421002,Hunan,China;Research Institute of Hunan University in Chongqing,Hunan University,Chongqing 400044,China;State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle,Hunan University,Changsha 410082,China)

机构地区：[1]湖南工学院智能制造与机械工程学院,湖南衡阳421002 [2]湖南大学重庆研究院,重庆400044 [3]湖南大学整车先进设计制造技术全国重点实验室,长沙410082

出　　处：《材料导报》2024年第20期243-251,共9页Materials Reports

基　　金：国家自然科学基金(52201074,52171115,U20A20275);湖南省自然科学基金(2024JJ5644);长沙市自然科学基金(kq2208420)。

摘　　要：利用分离式霍普金森压杆和多种显微表征方法,研究了不同热处理状态和加载路径下挤压WE43镁合金的室温动态力学响应行为。结果表明挤压WE43镁合金的各向异性较弱,其真应力-真应变曲线都为“C”形,屈服强度和极限强度都具有正的应变速率敏感性。不同热处理状态和加载路径下,挤压WE43镁合金都产生了较多的形变孪晶,同时伴有少量的孪晶交叉。孪晶虽然对热处理状态和加载路径都不敏感,但能够促进胞状位错亚结构的形成。当加载应变速率增至4120 s^(-1)时,在绝热温升及其诱导的动态回复作用下,孪晶密度反而降低。孪生和非基面滑移相协调是室温下挤压WE43镁合金的主导变形机制。基于经典J-C本构,采用应变和应变速率的多项式函数对应变硬化项和应变速率硬化项进行修正,构建了不同热处理状态和加载路径下挤压WE43镁合金的力学本构模型。拟合结果与实验的偏差均在±10%以内,相关系数R和平均相对误差AARE分别为0.952和3.28%。The dynamic mechanical behavior of an extruded WE43 magnesium alloy with various heat treatments under different loading paths at room temperature was investigated by split Hopkinson pressure bar and various microscopic characterization methods.The results show that the true stress-true strain curves of the extruded WE43 magnesium alloy feature a‘C’shape with a weak anisotropy.Both its yield strength and ultimate strength show positive strain rate sensitivity.Under different loading paths,a lot of deformation twins generate in the studied alloy with diffe-rent heat treatment states,accompanied by a small amount of twin intersections.Although twinning is insensitive to heat treatment and loading path,it can promote the formation of cellular dislocation substructures.When the applied strain rate increases to 4120 s^(-1),the density of twins decreases due to adiabatic temperature rise and induced dynamic recovery.Mutual coordination between twinning and non-basal slip is the dominant deformation mechanism of the extruded WE43 magnesium alloy at room temperature.Based on the classical J-C constitutive model,the strain hardening term and the strain rate hardening term were then modified by polynomial functions of strain and strain rate,and the mechanical constitutive functions under different loading paths were established for various heat-treated WE43 magnesium alloys.The deviations between the results of constitutive fitting and experiment were within±10%,and the correlation coefficient R and the average relative error AARE were 0.952 and 3.28%,respectively.

关 键 词：WE43镁合金 高速冲击 加载路径 力学响应 本构建模 

分 类 号：TH142.3[一般工业技术—材料科学与工程]