考虑位错密度的铝合金动态压缩晶体塑性有限元分析  

Crystal Plastic Finite Element Analysis of Dynamic Compression of Aluminum Alloy Considering Dislocation Density

作　　者：赵英杰 胡广 赵聃 张团卫[1,2,3] 马胜国 王志华 ZHAO Yingjie;HU Guang;ZHAO Dan;ZHANG Tuanwei;MA Shengguo;WANG Zhihua(Institute of Applied Mechanics,College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Key Laboratory of Material Strength&Structural Impact,College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Mechanics National Experimental Teaching Demonstration Center,College of Mechanical and Vehicle Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学机械与运载工程学院,应用力学研究所,太原030024 [2]太原理工大学材料强度与结构冲击山西省重点实验室,太原030024 [3]太原理工大学力学国家级实验教学示范中心,太原030024

出　　处：《太原理工大学学报》2023年第1期162-169,共8页Journal of Taiyuan University of Technology

基　　金：国家自然科学基金资助项目(11602158,12072220,11572214);山西省自然科学基金资助项目(202103021224042,201901D111088);中国博士后基金(2020M673473);山西省“1331工程”重点创新团队。

摘　　要：采用实验与晶体塑性有限元(CPFEM)相结合的方法,对7075-T6铝合金在动态压缩实验中的宏观力学响应及其微观结构的演化进行了分析。通过分离式霍普金森压杆(SHPB)对7075-T6铝合金进行了应变率为2 000 s-1的动态压缩实验,并使用电子背散射衍射技术(EBSD)对实验前后试件的微观结构进行了表征。修改了传统晶体塑性有限元模型中的强化模型和流动准则,引入位错密度作为内部状态变量,并探究了摩擦系数以及位错增殖系数和位错湮灭系数对试件宏观力学性能的影响。结果表明:位错增殖系数增大会导致材料的硬化行为加剧且极限强度提高,位错湮灭系数增大则会导致材料的极限强度下降,且弱化其硬化行为。通过实验与模拟的结果对比可以看出,晶体塑性有限元模型可以较为准确地预测动态压缩过程中试样内部织构的变化趋势,表现为生成了较多的Brass{110}<112>织构和Goss{110}<001>织构。Macroscopic mechanical response and microstructure evolution of 7075-T6 aluminum alloy during dynamic compression were investigated by experiments and crystal plastic finite element method(CPFEM). The dynamic compression experiment of 7075-T6 aluminum alloy with a strain rate of 2 000 s-1was carried out with a split Hopkinson pressure bar(SHPB). The microstructure of aluminum before and after dynamic compression was characterized by electron backscattering diffraction technique(EBSD). The internal state variables of dislocation density were introduced into the CPFEM model by modifying the strengthening model and the flow criterion. The effects of friction coefficient, dislocation multiplication coefficient, and dislocation annihilation coefficient on the macro mechanical properties of the specimens were investigated. The results show that the increase of dislocation multiplication coefficient aggravates the hardening behavior and increases the ultimate strength of the material, and the increase of dislocation annihilation coefficient reduces the ultimate strength of the material while weakens its hardening behavior. Through the comparison of experimental and simulation results, it could be seen that CPFEM accurately predicts the variation trend of the texture during dynamic compression, as more brass {110} <112> texture and Goss {110} <001> texture are generated.

关 键 词：晶体塑性 位错密度 织构 动态压缩 铝合金 

分 类 号：O344.1[理学—固体力学]