α-Fe中氦泡阻碍位错移动硬化的分子动力学研究  

Molecular dynamics study of hardening induced by helium bubbles impeding edge dislocation motion in α-Fe

作　　者：刘星 时靖谊 彭蕾[1] LIU Xing;SHI Jing-Yi;PENG Lei(School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230027, China;Advanced Energy Research Center, Shenzhen University, Shenzhen 518060, China;Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province,College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China)

机构地区：[1]中国科学技术大学核科学技术学院,合肥230027 [2]深圳大学新能源研究中心,深圳518060 [3]深圳大学光电工程学院光电子器件与系统(教育部/广东省)重点实验室,深圳518060

出　　处：《原子与分子物理学报》2018年第6期1029-1036,共8页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(U1730123)

摘　　要：基于周期性位错阵列模型,利用分子动力学方法,研究了α-Fe中1/2a0<111>{110}刃位错与3nm氦泡的相互作用导致硬化的过程,重点研究了不同温度下(300 K和623 K),氦空位比例对位错与3 nm氦泡作用机制影响的差异性.研究结果表明,当氦空位比例在0～1之间变化时,氦空位比例的变化对临界剪切应力的影响微弱,当氦空位比例在1～1.5之间变化时,氦泡内氦原子的数量的增加,临界剪切应力随之降低.氦空位比例升高至1.75时,高温623 K与室温相比,临界剪切应力反常升高,原因是高温引起的位错与氦泡的排斥机制:氦泡严重超压,与位错接触瞬间,沿位错拉伸侧踢出自间隙原子团簇,被位错吸收后产生割阶;由于位错割阶与超压氦泡同为压应力场,割阶被氦泡强烈排斥反弹.The interaction between1/2a0<111>{110}edge dislocation and3.0nm helium bubble with various Helium-to-vacancy ratios(He/V)and temperatures(300K and623K)inα-Fe were studied by using molecular dynamics based on the periodic arrays of dislocations model.The results show that the release stress of dislocation weakly depends on He/V ratios ranging from0to1;when He/V ratio varies from1.0to1.5,increasing the number of helium atoms in the helium bubble has positive effects on the climbing of dislocation;for the helium bubble(He/V=1.75),when the temperature rises from300K to623K,the increase of the bubble pressure caused by the increase of temperature changes the interaction mechanism and caused the increase of CRSS.A repel mechanism of dislocation and helium bubble interaction is proposed to elucidate the effect of temperature.When the helium bubble is heavily over-pressured,the edge dislocations absorbs the interstitials and clusters which are punched out from the bubble,thus forms a superjog and is repelled from the bubble since there both are compressive stress fields around the dislocation jog and over-pressured helium bubble.

关 键 词：氦泡 刃位错 氦空位比例 分子动力学 

分 类 号：O65[理学—分析化学]