横向限制下凝固微观组织演化的相场法模拟

凝固过程中横向限制挡板的存在对晶体微观结构的演化存在重要的影响, 不同性质的横向挡板将产生不同的限制效应, 对最终凝固微观组织形成起着决定性作用. 本文利用非等温相场模型, 定性地模拟了纯金属Ni凝固过程中横向限制的存在对其枝晶微观形貌演化的影响, 研究了不同尺寸及性质的横向挡板对枝晶微观结构形成的影响, 讨论了横向限制对不同初始枝晶间距枝晶形貌发展的作用. 计算结果表明, 横向限制挡板的存在将直接影响凝固过程中微观组织的形貌演化过程并最终改变微观结构. 随着横向挡板间距的减小, 微观组织变化更加明显; 挡板初始温度越低, 枝晶形貌改变越明显; 初始枝晶间距越大, 形貌变化越明显; 不同挡板高度对微观结构具有基本相同的影响.关键词：相场模拟微观组织演化横向限制

Phase-field simulation of solidified microstructure evolution in the presence of lateral constraint

Lateral constrain in the presence of melting has a significant effect on microstructure evolution of crystal growth, and this effect is related to the size and property of lateral constrain, thus determining microstructure formation during solidification. In the paper, microstructure evolution in the presence of lateral constrain during the solidification of pure Ni metal is simulated using a non-isothermal phase-field model. Effects of size and properties of lateral constrain are simulated and studied, also microstructures formed at different initial dendritic arm distances are discussed. Results indicate that the presence of lateral constrain has a direct influence on pattern evolution which determines the microstructure formation. Microstructure changes significantly with lateral constrain distance turning small, initial constrain temperature low becoming low and initial dendrite arm distance growing. Different heights of lateral constrains have almost the same effects on microstructure change during solidification.
Keywords：phase-field simulationmicrostructure evolutionlateral constraint