冲击加载下多晶铝的晶体塑性有限元模拟  

Crystal Plasticity Finite Element Simulation of Polycrystal Aluminum under Shock Loading

作　　者：叶常青 陈然 刘桂森 刘静楠 胡建波[2] 俞宇颖[2] 王栋 陈开果 沈耀[1] YE Changqing;CHEN Ran;LIU Guisen;LIU Jingnan;HU Jianbo;YU Yuying;WANG Dong;CHEN Kaiguo;SHEN Yao(School of Material Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;National Key Laboratory of Shock Wave and Detonation Physics,Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621999,Sichuan,China;Northwest Institute of Nuclear Technology,Xi’an 710024,Shaanxi,China;Department of Physics,National University of Defense Technology,Changsha 410073,Hunan,China)

机构地区：[1]上海交通大学材料科学与工程学院,上海200240 [2]中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室,四川绵阳621999 [3]西北核技术研究院,陕西西安710024 [4]国防科技大学物理系,湖南长沙410073

出　　处：《高压物理学报》2022年第6期137-149,共13页Chinese Journal of High Pressure Physics

基　　金：科学挑战专题(TZ2018001)。

摘　　要：在多晶材料中,不同取向晶粒间的晶界往往对材料在冲击加载下的动力学响应有极大的影响。在单晶晶体塑性模型的基础上,通过考虑晶界与位错相互作用的微观机理,建立了一个包含晶界阻力、几何必需位错以及背应力的多晶晶体塑性模型,并模拟研究了基于Voronoi几何模型的多晶铝在冲击加载下的力学响应。结果表明:冲击波后的晶界单元存在极高的残余剪应力,而晶粒内部单元的剪应力趋近于零;晶界附近存在较大的塑性变形梯度,产生大量沿晶界分布的几何必需位错和背应力;由滑移不连续性引起的晶界阻力是造成冲击波后大量残余剪应力的主要因素,而几何必需位错和背应力对剪应力松弛程度的影响较小。In polycrystalline materials,the grain boundaries between grains with different orientations have a great influence on the dynamic response of material under shock loading.On the basis of the single crystal plasticity model,a polycrystal plasticity model containing grain boundary obstacle,geometrically necessary dislocations(GND)and back-stress is established by considering the microscopic mechanism of the interaction between grain boundaries and dislocations.Based on this model,the mechanical response of polycrystalline aluminum with Voronoi geometry under shock loading was studied through simulations.The results show that:(1)the grain boundary elements after the shock loading have a very high residual shear stress,while the shear stress of the element within the grain tends to be zero;(2)a large plastic deformation gradient is found near the grain boundary,resulting in a large number of GND and back stress distributed along the grain boundary;(3)the grain boundary obstacle caused by the slip discontinuity is the main factor causing the large amount of residual shear stress,while the GND and back stress have little influence on the extent of shear stress relaxation.

关 键 词：晶体塑性 冲击加载 晶界效应 晶界阻力 几何必需位错 背应力 

分 类 号：O347.3[理学—固体力学] O521.2[理学—力学]