CAJ | 학술논문

采用相场方法研究了液相扩散系数对 Al356.1合金凝固过程初晶(Al)相显微组织演变的影响。在相场模拟中，采用了两套液相扩散系数，而其他热物理参数和数值参数则保持一致。第一套液相扩散系数只考虑随温度变化的 Arrhenius 类型的杂质扩散系数，而第二套则为随温度和成分变化的精准的液相原子移动性数据库。对于第二套液相扩散系数，还分析了扩散系数矩阵中的非对角项对Al356.1合金凝固过程中显微组织演变的影响。通过相场模拟发现：在3种液相扩散系数情况下，初晶(Al)相的形貌、枝晶尖端的速率和枝晶前端的成分曲线均有不同。研究结果表明：精确的液相原子移动性参数对定量模拟凝固过程显微组织演变是非常重要的。
채용상장방법연구료액상확산계수대 Al356.1합금응고과정초정(Al)상현미조직연변적영향。재상장모의중，채용료량투액상확산계수，이기타열물리삼수화수치삼수칙보지일치。제일투액상확산계수지고필수온도변화적 Arrhenius 류형적잡질확산계수，이제이투칙위수온도화성분변화적정준적액상원자이동성수거고。대우제이투액상확산계수，환분석료확산계수구진중적비대각항대Al356.1합금응고과정중현미조직연변적영향。통과상장모의발현：재3충액상확산계수정황하，초정(Al)상적형모、지정첨단적속솔화지정전단적성분곡선균유불동。연구결과표명：정학적액상원자이동성삼수대정량모의응고과정현미조직연변시비상중요적。
The effect of liquid diffusion coefficients on the microstructure evolution during solidification of primary (Al) phase in Al356.1 alloy was investigated by means of the phase-field simulation using two sets of diffusion coefficients in liquid phase, while fixing other thermophysical and numerical parameters. The first set is only with impurity coefficients of liquid phase in Arrhenius formula representing only the temperature dependence. While the second set is with the well-established atomic mobility database representing both temperature and concentration dependence. For the second set of liquid diffusion coefficients, the effect of non-diagonal diffusion coefficients on the microstructure evolution in Al356.1 alloy during solidification was also analyzed. The differences were observed in the morphology, tip velocity and composition profile ahead of the tip of the dendrite due to the three cases of liquid diffusivities. The simulation results indicate that accurate databases of mobilities in the liquid phase are highly needed for the quantitative simulation of microstructural evolution during solidification.