定向退火条件下柱状晶形成及连续扩展的相场模拟

Phase field simulation of formation and continuous propagation of columnar grain structure during directional annealing

基于定向退火条件下的移动热区模型,采用相场法研究定向退火条件下热区宽度对多晶材料中柱状晶形成及连续扩展的影响。模拟结果表明:增加热区宽度有利于形成柱状晶结构,且所得柱状晶的长宽比随着热区宽度的增加而增大;当热区移动速率一定时,柱状晶连续扩展所需临界热区宽度小于形成柱状晶所需临界热区宽度;当热区宽度大于初始晶粒直径的1.5倍时,热区宽度对柱状晶连续扩展的热区移动临界速率的影响很小。

Based on the moving hot zone model under directional annealing, the effects of the hot zone width on the formation and continuous propagation of columnar grain structure during directional annealing in polycrystalline materials were studied by phase field method. The simulation results show that increasing hot zone width is beneficial to the formation of columnar grain structure, and the aspect ratio of the columnar grain increases with increasing the hot zone width. For a given zone speed, the critical hot zone width for propagation of columnar grain is smaller than that for its formation. When the hot zone width is 1.5 times greater than the initial grain diameter, the effect of the hot zone width on critical hot zone speed necessary for the continuous propagation of columnar grain structure is rarely small.