Zr纳米粒子内HCP-BCC堆积结构转变的分子动力学模拟  

Molecular dynamics simulations of HCP-BCC packing transformation for Zr nanoparticles

作　　者：王之涵 于宁 张林 WANG Zhi-Han;YU Nin;ZHANG Lin(Key Laboratory for Anisotropy and Texture of Materials Ministry of Education,Northeastern University,Shenyang 110819,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学材料各向异性与织构教育部重点实验室,沈阳110819 [2]东北大学轧制技术及连轧自动化国家重点实验室,沈阳110819 [3]东北大学材料科学与工程学院,沈阳110819

出　　处：《原子与分子物理学报》2021年第6期53-61,共9页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(51671051);国家重点研发计划(2016YFB0701304)。

摘　　要：本文采用基于嵌入原子势的分子动力学方法模拟了不同粒径的Zr纳米粒子在升温过程中HCP-BCC结构转变的路径.通过对粒子在升温过程中的势能差分曲线的计算,分别确定了小粒径、较大粒径和大粒径粒子的结构转变温度区间,并使用二分法进一步确定了转变温度点.然后借助对结构转变温度点处的形状因子、键对占比和原子堆积结构随弛豫时间的变化的模拟计算,确定了驰豫过程中堆积结构的演变过程.计算结果表明,小粒径粒子存在着多个结构转变温度点,并会在较低的结构转变温度点处出现多结构共存现象,其驰豫过程就是不同结构间相互竞争的过程.随着粒径的增大,在较高温度点处虽然仍会出现多结构共存,但粒子内的大部分原子堆积为BCC结构,并且在大粒径粒子内会出现明显的界面区.In this paper, molecular dynamics based on embedded atom method is used to simulate the HCP-BCC structural transformation path of zirconium nanoparticles with different sizes during the heating process. By calculating the different potential energy curves of the particles, we determined the structure transition temperature ranges of small-size, the relative larger-size and large-size particles, and hence the corresponding points of temperature transition. Through calculating the shape factor, pair fraction, and the change of the atomic packing structure within the relaxation time at the structural transition temperatures, the evolution of the packing structure during the relaxation process was observed. The simulation results show that there are multiple structural transition temperature points for the small-sized particle, and the coexistence of multiple structures occurs at a lower structural transition temperature point. The relaxation process is a process of competition between different structures. As the particle size increases, multiple structures coexist at higher temperatures, and most of the atoms in the particles will be packed into the BCC structure. The large-size particles have obvious interface regions.

关 键 词：纳米粒子 相变 分子动力学 嵌入原子势 

分 类 号：O411.2[理学—理论物理]