Cooling rate dependence of polymorph selection duringrapid solidification of liquid metal zinc
(1. College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, China;
2. Department of Information Engineering, Gannan Medical University, Ganzhou 341000, China;
3. Laboratory for Simulation and Modelling of Particulate Systems, School of Materials Science and Engineering, University of New South Wales, Sydney NSW 2052, Australia;
4. School of Physics and Microelectronic Science, Hunan University, Changsha 410082, China)
2. Department of Information Engineering, Gannan Medical University, Ganzhou 341000, China;
3. Laboratory for Simulation and Modelling of Particulate Systems, School of Materials Science and Engineering, University of New South Wales, Sydney NSW 2052, Australia;
4. School of Physics and Microelectronic Science, Hunan University, Changsha 410082, China)
Abstract: The polymorph selection during rapid solidification of zinc melt was investigated by molecular dynamics simulation. Several methods including g(r), energy, CNS, basic cluster and visualization were used to analyze the results. The results reveal that the cooling rate has no observable effect on the microstructure as T>Tc(Tc is the onset temperature of crystallization); and at the first stage of crystallization, although microstructures are different, the morphologies of nucleus are similar, which are composed of HCP and FCC layers; the polymorph selection of cooling rate finally takes place at the second stage of crystallization: at a high cooling rate, the rapid increase of FCC atoms leads to a FCC crystal mixed with less HCP structures; while at a low cooling rate, HCP atoms grow at the expense of FCC atoms, resulting in an almost perfect HCP phase. The results reveal that the cooling rate is one of the important factors for polymorph selection.
Key words: polymorph selection; crystal structure; rapid solidification; metal zinc; molecular dynamics simulation