Al凝固特性随冷却速率变化规律的分子动力学模拟  

Molecular Dynamic Simulation of the Dependence of Solidification Behaviour of Aluminum on the Cooling Rate

作　　者：坚增运[1] 相敏[1] 朱满[1] 许军锋[1] 常芳娥[1] 

机构地区：[1]西安工业大学材料与化工学院,西安710021

出　　处：《西安工业大学学报》2015年第4期311-316,共6页Journal of Xi’an Technological University

基　　金：国家自然科学基金项目(51371133;51171136;51301125;51401156);国家973项目(2011CB610403)

摘　　要：对Al熔体在不同冷却速率下的凝固行为及其组织进行了分子动力学模拟.研究结果发现金属的凝固特性受冷却速率影响.当冷却速率小于1.0×1012.5 K·s-1时,金属Al凝固时的形核过冷度随着冷速的不断增加而增大,凝固后形成由面心立方结构和密排六方结构镶嵌而成的晶体组织;当冷却速率大于1.0×1015.0 K·s-1时,Al凝固后形成非晶态组织;冷却速率介于二者之间时,Al凝固后形成晶态和非晶态的混合组织.随着冷速的增大,最大晶态团簇中FCC结构原子的数目逐渐减少,HCP结构团原子的数目先增加后减小.The solidification behavior of aluminum melt under the different cooling rate is simulated by using molecular-dynamics（MD） method. It is found that the solidification behavior of aluminum depends on the cooling rate. When the cooling rate is less than 1.0×10^12.5 K·s^-1 , the undercooling of aluminum melt increases with increasing the cooling rate and the mosaic crystalline structure formed by FCC structure and HCP structure is obtained after the solidification. When the cooling rate is greater than 1.0×10^15.0 K·s^-1,the solidification structure is the amorphous. When the cooling rate is in the region from 1.0×10^12.5 K·s^-1to 1.0×10^15.0 K·s^-1, a mixture structure consisting of the crystalline and the amorphous is obtained after the solidification. With increasing the cooling rate, the atom number of the FCC structure in the largest crystalline cluster decreases gradually while the atom number of the HCP structure in the maximum crystalline cluster first increases and then decreases.

关 键 词：分子动力学方法 团簇 冷速 均质形核过冷度 

分 类 号：TG111.4[金属学及工艺—物理冶金] TG146.21[金属学及工艺—金属学]