基于离散位错动力学的纳米层状铜异质结构诱导协同强化研究  

Study on heterostructure induced synergistic strengthening of nanolayered copper based on discrete dislocation dynamics

作　　者：张逸安 陆宋江 赵建锋 陆晓翀 刘宝玺 张旭[1] ZHANG Yi-an;LU Song-jiang;ZHAO Jian-feng;LU Xiao-chong;LIU Bao-xi;ZHANG Xu(School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu 610097,China;Institute of Systems Engineering,China Academy of Engineering Physics(CAEP),Mianyang 621999,China;School of Aeronautics and Astronautics,Sichuan University,Chengdu 610065,China;School of Materials Science and Engineering,Hebei University of Technology,Tianjin 300130,China)

机构地区：[1]西南交通大学力学与航空航天学院,四川成都610097 [2]中国工程物理研究院总体工程研究所,四川绵阳621999 [3]四川大学空天科学与工程学院,四川成都610065 [4]河北工业大学材料科学与工程学院,天津300130

出　　处：《塑性工程学报》2024年第11期140-150,共11页Journal of Plasticity Engineering

基　　金：国家自然科学基金优秀青年科学基金资助项目(12222209)。

摘　　要：利用三维多尺度离散位错动力学(DDD)方法对粗/细晶交替的纳米层状铜力学行为及其变形机制进行了研究。在多尺度DDD框架内分别构筑了粗/细晶叠层的多晶模型和对应的粗晶、细晶多晶模型,并采用基于粗粒化方法的位错穿透晶界模型描述了位错与晶界之间的相互作用。单轴拉伸模拟结果表明,层状材料的屈服应力和应变硬化均大于混合法则预测值,表明层状结构诱导了额外强化。进一步的微观结构演化分析表明,在层状材料中,位错在粗晶和细晶中激活并滑移,细晶中位错开动以后很快就会被晶界阻碍,而粗晶中的位错则会滑过整个粗晶层产生更大的塑性应变,从而诱发粗晶层和细晶层间产生应变分配。界面处的应变梯度促进几何必需位错累积,并产生异质变形诱导(HDI)强化。因此,纳米层状铜表现出更强的包辛格效应。Using the three-dimensional multi-scale discrete dislocation dynamics(DDD)method to study the mechanical behaviors and deformation mechanism of nanolayered copper with alternating coarse/fine grains.The polycrystalline model with coarse/fine grains stacking and corresponding coarse grains and fine grains polycrystalline models were constructed within the multi-scale DDD framework,and the dislocation penetration grain boundary model based on coarsening method was used to describe the interaction between dislocations and grain boundaries.The uniaxial tensile simulation results show that both the yield stress and strain hardening of the layered material are greater than the predicted values of mixing rule,indicating that the layered structure induces additional strengthening.Further microstructure evolution analysis shows that in layered materials,dislocations are activated and slip in both coarse grains and fine grains.Once dislocations move in fine grains,they are quickly obstructed by grain boundaries,while the dislocations in coarse grains slide across the entire coarse grain layer to generate greater plastic strain, thereby inducing strain distribution between coarse grain layers and fine grain layers. The strain gradient at the interface promotes the accumulation of geometrically necessary dislocations and generates hetero deformation in-duced (HDI) strengthening. Therefore, the nanolayered copper exhibits stronger Bauschinger effect.

关 键 词：离散位错动力学 层状材料 微结构演化 塑性行为 包辛格效应 

分 类 号：TG146.1[一般工业技术—材料科学与工程]