CoCrFeMnNi高熵合金冲击波响应与层裂强度的分子动力学研究  

SHOCK WAVE RESPONSE AND SPALL STRENGTH IN CoCrFeMnNi HIGH-ENTROPY ALLOY: A MOLECULAR DYNAMICS STUDY

作　　者：杜欣 袁福平[2] 熊启林 张波[1] 阚前华[1] 张旭[1] Du Xin;Yuan Fuping;Xiong Qilin;Zhang Bo;Kan Qianhua;Zhang Xu(School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu 610031,China;State Key Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China;School of Aerospace Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]西南交通大学力学与航空航天学院,成都610031 [2]中国科学院力学研究所非线性力学国家重点实验室,北京100190 [3]华中科技大学航空航天学院,武汉430074

出　　处：《力学学报》2022年第8期2152-2160,共9页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(11872321,12192214,12072295);非线性力学国家重点实验室开放基金(2022年)资助项目。

摘　　要：高熵合金未来有望应用于航空航天和深海探测等领域,并且不可避免地会受到极端冲击载荷作用,甚至会发生层裂.本文采用分子动力学(MD)方法,研究了CoCrFeMnNi单晶高熵合金冲击时的冲击波响应、层裂强度以及微观结构演化的取向相关性和冲击速度相关性.模拟结果表明,在沿[110]和[111]方向进行冲击时产生了弹塑性双波分离现象,且随着冲击速度的增加呈现出先增强后减弱的变化趋势,但在沿[100]方向冲击时未出现双波分离现象.在冲击过程中,大量无序结构产生且随冲击速度的增加而增加,使得层裂强度随冲击速度的增加而减小.此外,层裂强度也具有取向相关性.沿[100]方向冲击时产生了大量体心立方(BCC)中间相,抑制了层错以及无序结构的产生,使得[100]方向的层裂强度最高;层裂初期微孔洞形核区域无序结构含量大小关系的转变,使得[111]方向的层裂强度在冲击速度较低时(U_(p)≤0.9 km/s)大于[110]方向,而在冲击速度较大时(U_(p)≥1.2 km/s)略小于[111]方向.研究成果有望为CoCrFeMnNi高熵合金在极端冲击条件下的应用提供理论支撑和数据积累.High-entropy alloys are expected to be used in aerospace,deep-sea exploration and other fields in the future,and will inevitably be affected by extreme shock loading,even will occur spall fracture.In this work,the molecular dynamics(MD)method is used to study the orientation and shock velocity dependence of the shock wave response,spall strength and microstructure evolution of single-crystal CoCrFeMnNi high-entropy alloys.The simulation results show that the elastoplastic two-wave separation phenomenon occurs when the shocking along the[110]and[111]directions and shows a trend of first strengthening and then weakening with the increase of the shock velocity.However,there is no two-wave separation phenomenon when the shocking along the[100]direction.During the shocking process,a large number of disordered structures are generated and increase with the increase of the shock velocity,which makes the spall strength decreases with the increase of shock velocity.In addition,the spall strength also exhibits orientation dependence.A large number of body-centered cubic(BCC)intermediate phases are generated when the shocking along the[100]direction,which inhibits the generation of stacking faults and disordered structures,making the highest spall strength in the[100]direction;The transformation of the relationship of the content of disordered structure in the nucleation area of microvoids at the early stage of spallation,making the spall strength in the[111]direction is higher than that in the[110]direction when the shocking velocity is low(U_(p)≤0.9 km/s),and slightly lower than that in the[110]direction when the shocking velocity is large(U_(p)≥1.2 km/s).The research results are expected to provide theoretical support and data accumulation for the application of Co Cr Fe Mn Ni high-entropy alloys under extreme shock conditions.

关 键 词：高熵合金 弹塑性双波分离 层裂强度 取向相关性 冲击速度相关性 分子动力学模拟 

分 类 号：O347.3[理学—固体力学]