过冷纯金属熔体中热扩散系数对其枝晶生长的影响

The effects of thermal diffusivity on dendrite growth in subcooled pure metals

采用相场模型和有限差分方法,模拟了过冷纯金属熔体的枝晶生长,计算区域为二维正方形均匀网格.建立了不同热扩散条件下尖端过冷度、速度、半径随时间变化的关系;此外研究发现枝晶稳定生长时,其尖端过冷度和速度与热扩散系数成正比,尖端半径与热扩散系数成反比.

Dendrite growth has been simulated with the phase field method and finite difference schemes on a two dimensional rectangular domain with a uniform square mesh. The relationships of dendrite tip subcooling, velocity and radius with dimensionless time have been established, respectively, at several thermal diffusivity levels. It is found that the dendrite steady-state tip subcooling and velocity are roughly in proportion to thermal diffusivity, respectively, and radius is in inverse proportion to thermal diffusivity.