Molecular Dynamics Simulations Of The Under-cooled Liquid Metal's Thermal Properties

Rapid solidification of supercooled liquid metals offers a promising way forpreparing the high performance materials. The thermal properties of undercooledliquid metals play an important role in the prediction and control of this solidificationprocess. Based on the available research of the undercooled liquid thermal properties,this thesis adopts molecular dynamics method to investigate the thermal properties ofundercooled liquid metal. The main results can be summarized as following aspects.The effect of different potential models on the structure and heat capacity ofliquid metal are simulated and analyzed. The results show that the prediction of liquidmetal structure is comparatively insensitive to different versions of the EAM model,while the prediction of specific heat demands a more rigorous potential than thestructure predictions do. The potential model which embodies the atomseparation-energy relation in the Rose' equation can predict the heat capacityaccurately. Johnson's potential model can predict the structure and heat capacity ofliquid metals accurately, and is simpler than other equations. Therefore, Johnson'spotential model is fit for the simulation of the liquid metal's thermal properties.The density and heat capacity of liquid metal under constant pressure aresimulated by the constraint isobar-isothermal ensemble. Different with the availablesimulation results, the simulated density and heat capacity are well agree with theavailable experimental results, the difference is less than 4% for density and 5% forspecific. This results show the undercooled liquid metal's thermal properties can bepredicted accurately by the molecular dynamics simulations which adopt the fitfulpotential model and right simulation method.The rapid cooling process of silver are carried out by molecular dynamicssimulation. The glass transition is found by the observation of the thermal properties,structure parameter and dynamics characteristic. These results show that the glasstransition of silver can be fulfilled in the quick cooling process.Parallel molecule dynamics simulations with 4,000,000 molecules on the clustercomputer system are realized and optimized. The optimized calculation has highparallel efficiency and wide expansibility, which pave a firm foundation to the furtherresearch on rapid solidification of the undercooled liquid metal.