过冷金属熔体中枝晶生长的各向异性效应
Anisotropic effect of equiaxed dendritic growth in a undercooled molten metal
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摘要: 基于Karma-Rappel相场模型,模拟了纯金属在量纲为1过冷度为0.45时等轴枝晶生长过程中晶粒形貌和温度场的变化.研究了不同各向异性条件下等轴晶晶粒形貌的演化过程.模拟结果显示,各项异性系数的大小对晶粒的形貌有重要影响.当各项异性为0.05时,枝晶在生长过程中出现了"颈缩"现象,枝晶中温度梯度最大的方向总是与最优生长方向保持一致.Abstract: Based on the Karrna-Rappel phase field model, the equiaxed dendritic growth and change in temperature field in a pure molten metal were numerically simulated at an initial dimensionless supercooling of 0.45. Morphological evolvement of dendrites at various anisotropic coefficients was investigated. The result shows that anisotropic coefficient significantly affects the dendrite morphology. During dendritic growth, obvious necking phenomenon appears as the anisotropic coefficienf is 0.05. The preferred growth direction of dendrites is always kept consistent with that of the highest temperature gradient.