动态冲击载荷下7003铝合金的力学响应行为及力学本构建模  

Mechanical Response Behavior and Mechanical Constitutive Modeling of 7003 Aluminum Alloy Under Dynamic Impact Load

作　　者：叶拓 邱飒蔚 夏二立 郭鹏程 吴远志[1] 李落星[2] 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,Chongqing 400044,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

出　　处：《材料导报》2024年第13期225-232,共8页Materials Reports

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

摘　　要：采用分离式霍普金森压杆装置对7003铝合金在不同应变速率下的室温动态力学响应行为进行了研究。结果表明:实验用7003铝合金的流变应力随应变速率的增加而增加,表现出正的应变速率敏感性,当加载应变速率增加至4100 s^(-1)时,剪切变形局域化所产生的绝热温升软化完全抵消了应变硬化和应变速率硬化,导致其流变应力在变形中期便随加载应变的增加而逐渐降低。随加载应变的增加,位错不断增殖使得位错密度不断增加。同时,这些位错在晶界处不断地塞积,并逐渐演变成胞状位错亚结构,导致位错密度逐渐达到饱和。通过优化原始J-C本构的应变硬化项、应变速率系数C和n,并引入绝热温升修正项,构建了能够准确预测7003铝合金在不同变形条件下应力响应行为的力学本构模型。拟合结果与实验结果的偏差均在±10%以内,预测值与实验值的相关系数(R)和平均相对误差(AARE)分别为99.17%和1.3%。The dynamic mechanical response behavior of 7003 aluminum alloy at room temperature and different strain rates was studied using a split Hopkinson pressure bar.The results show that the flow stress of the 7003 aluminum alloy increases with the increase of applied strain rate,showing a positive strain rate sensitivity.When the loading strain rate increases to 4100 s^(-1),the adiabatic temperature rise softening caused by localization of shear deformation completely counteracts the strain hardening and strain rate hardening.As a result,the flow stress decreases gradually with the increase of loading strain in the middle stage of deformation.With the increase of loading strain,the dislocation density increases due to the proliferation of dislocations.At the same time,these dislocations continue to pile up at grain boundaries,and gradually evolve into cellular dislocation substructures,resulting in the saturation of dislocation density.By optimizing the strain hardening term,strain rate coefficient C and n of the original J-C constitutive,and introducing a correction term of adiabatic temperature rise,a mechanical constitutive model which can accurately predict the stress response behavior of 7003 aluminum alloy under different deformation conditions is constructed.The deviations between the fitting results and the experimental results are all within±10%,and the correlation coefficient(R)and average relative error(AARE)between the predicted and experimental values are 99.17%and 1.3%,respectively.

关 键 词：7003铝合金 动态冲击 力学响应 本构建模 组织演变 

分 类 号：TH142.3[一般工业技术—材料科学与工程]