不同尺寸Cu_(64)Zr_(36)纳米液滴的快速凝固过程分子动力学模拟  

Molecular dynamics simulation of rapid solidification of Cu_(64)Zr_(36) nanodrops of different sizes

作　　者：韦国翠 田泽安 Wei Guo-Cui;Tian Ze-An(Institute of Advanced Optoelectronic Materials and Technology,School of Big Data and Information Engineering,Guizhou University,Guiyang 550025,China;College of Computer Science and Electronic Engineering,Hunan University,Changsha 410082,China)

机构地区：[1]贵州大学大数据与信息工程学院,先进光电材料与技术研究所,贵阳550025 [2]湖南大学信息科学与工程学院,长沙410082

出　　处：《物理学报》2021年第24期252-262,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51661005,U1612442);贵州大学智能制造产教融合创新平台及研究生联合培养基地(批准号:2020-520000-83-01-324061)资助的课题.

摘　　要：由于冷却技术和合金非晶形成能力的限制,实验室难以得到大块非晶,而纳米液滴的快速冷却要相对容易,因此纳米液滴的模拟研究更容易得到实验的验证.本文运用分子动力学方法,模拟不同尺寸的Cu_(64)Zr_(36)纳米液滴在1.0×10^(12) K/s冷却速率下的凝固过程,并采用平均原子能量、双体分布函数、三维可视化和最大标准团簇分析等方法分析其微观结构的演化.对能量曲线和微观结构短程序特征长度的统计分析表明,所有纳米液滴的凝固过程都经历了液-液相变和液-固相变,最后形成了非晶态纳米颗粒.拓扑密堆(topologically close-packed,TCP)结构的演化过程能充分体现纳米液滴两次相变的基本特征,但二十面体不能.从TCP团簇的角度,纳米液滴的整个凝固过程可以分为坯胎、聚集、长大和粗化4个阶段.TCP结构能体现出非晶纳米液滴和颗粒的基本结构特征,对于完善凝固理论具有重要意义.It is difficult to obtain bulk amorphous alloys experimentally due to the limitation of cooling technology and the ability to form amorphous alloy.However,the rapid cooling of nano-droplets is relatively easy,so the simulation research of nano-droplets is easier to verify experimentally.In this work,the molecular dynamics simulation for the rapid cooling of Cu_(64)Zr_(36) nano-droplets of different sizes is conducted at a cooling rate of 1.0×10^(12) K/s,and the evolution of microstructure is analyzed in terms of the average potential energy,the pair distribution function,the three-dimensional visualization,and the largest standard cluster analysis.The analysis of the energy curves and the characteristic length for short-range-ordered microstructure show that the solidification process for all nano-droplets undergoes liquid-liquid transition and liquid-solid transition,and finally forms amorphous nanoparticles.Comparing with the icosahedron,the evolution of the topologically close-packed(TCP)structures can reflect the basic characteristics of phase transitions effectively.Based on the evolution of TCP clusters,the entire solidification process of nano-droplets can be divided into four stages:embryo,aggregation,growth and coarsening.The TCP structure embodies the basic structural characteristics of amorphous nano-droplets and particles,which is of great significance in perfecting the solidification theory.

关 键 词：CuZr 合金 TCP 结构 LaSC 分子动力学模拟 凝固过程 

分 类 号：TB383.1[一般工业技术—材料科学与工程]