【摘要】 相场方法以Ginzburg　Landau相变理论为基础,通过微分方程反应扩散、有序化势及热力学驱动力的综合作用。本文采用相场模型模拟了纯物质凝固过程的等轴枝晶的演化和枝晶的形貌,并针对金属镍进行了二维数值模拟,计算了过冷熔液中的枝晶生长。在相场方程中采用均匀网格的显示有限差分方法求解。模拟结果显示了枝晶的形貌和生长过程,包括一次臂和二次臂,以及枝晶生长过程中出现的生长竞争和"缩颈"现象。更多还原

【Abstract】 The phase field method is based on the general GinzburgLandau theory of phase transitions. It reflects these basic ideas in terms of differential equations, where diffusion, ordering potential and thermodynamic driving force are represented by operations of appropriate symmetry. In this paper, the morphology of dendrite and the equiaxied dendrite evolution during the solidification process of pure material nickel were numerically simulated by using the phase field method. The phase field model equations were solved by using the explicit finite difference method on an uniform mesh. The simulated results show the dendrite crystal growth process, including primary and secondary arms, the competition between the dendritic arms as well as the "necking" during the dendrite growth process.更多还原