Effect of cluster connection on crystal structure of Cu10Ag90 during rapid solidification
The crystals obtained by rapid solidification usually form multiple twin structures,butthe formation has been a mystery.The molecular dynamics simulations of the rapid solidification process of Cu10Ag90 alloy at 0,20 and 40 GPa pressures were used in this paper to form fivefold twins,lamellar twins and complex crystals,respec-tively.The evolution of the short-range ordered structure and the connection forms between crystal clusters were analyzed by the largest standard cluster analysis(LaSCA).It is found that the crystallization transition tempera-ture Tc increases with increasing pressure,and the average atomic potential energy also increases.Amorphous common neighbor sub-cluster(CNS)will transform into crystalline CNS when the temperature drops to Tc,while the number of crystalline clusters increases dramatically and the structural order is enhanced.In addition,by analyzing the connections between crystal clusters,it is found that the fivefold twin central cluster truncated-decahedron(tDh)can only be connected to HCP with the same S422 to form a fivefold twin axis;FCC and HCP have the same S421,but can only form a lamellar structure by connecting each other's top or bottom atoms as each other's central atoms;although BCC and FCC,HCP do not have a common CNS,but they can be connected by the D-S6 structure and its distorter,and the diversity of their connections is the main reason for the forma-tion of complex crystals.These results provide a new understanding for the study of different arrangements of crystal structures.
万方数据
维普
