作　　者： ; ; ; ;

机构地区： 嘉应学院物理与光信息科技学院

出　　处： 《材料科学与工程学报》 2014年第6期830-839,共10页

摘　　要： 采用分子动力学方法对由5万个液态金属铜(Cu)原子构成的系统在不同冷却速率下的凝固过程中对微观结构演变的影响进行了模拟跟踪研究。运用双体分布函数g(r)曲线、HoneycuttAndersen(HA)键型指数法、新的原子团类型指数法(CTIM-2)和可视化分析等方法,对凝固过程中微观结构的演变特性进行了分析研究。结果发现:由非晶体向晶体转变的临界速度约为1.0×1013 K/s,在此冷速下系统最终形成非晶体和晶体混合共存的结构;在冷速为1.0×1014 K/s时,非晶转化温度约为673K;在以4.0×1012 K/s速度冷却时,系统从673K就开始结晶,并形成以1421和1422二种键型或由这二种键型构成的面心立方(fcc)(12 0 0 0 12 0)和六角立方(hcp)(12 0 0 0 6 6)基本原子团为主的晶体结构。同时发现,冷速对系统中的fcc结构和hcp结构的相对比例有显著的影响,冷速越低,fcc基本原子团簇结构越多。 A tracing simulation study has been performed for the effects on evolution of microstructures during solidification process of 50000 Cu atoms in liquid stater at different cooling rates by using the molecular dynamics method.The pair distribution function g(r)cures,the bond-type index method of HoneycuttAndersen(HA),the new cluster-type index method(CTIM-2)and visualization analysis have been used to analyze and study the evolution characterisitics of microstructures in the solidification process.It is found that a critical cooling rate is about 1.0×1013 K/s for transition from amorphous to crystalliine,and a crystalline and amorphous coexistence structure is formed finally in the system at this cooling rate.At the cooling rate of1.0×1014 K/s,the glass transition temperature TCis about 673 K.When the cooling rate is 4.0×1012 K/s,the crystallization starts from 673 Kin the system,and the crystal structures are formed mainly with the 1421and1422bond-types or fcc(12 0 0 0 12 0)and hcp(12 0 0 0 6 6)basic clusters.Meanwhile,it has been found that there are obvious effects of the cooling rate on the relative proportion of the fcc and hcp basic clusters,the lower the cooling rate is,the more the fcc basic cluster.

关 键 词： 液态金属 凝固过程 微观团簇结构演变 分子动力学模拟 多体势

领　　域： [金属学及工艺] [一般工业技术] [金属学及工艺]