ABSTRACT

In this study, a computational fluid dynamics (CFD) model is employed to optimise the melt pouring temperature during Low superheat casting (LSC) of the Al-15 Mg₂Si-4.5Si composite. The die cavity considered to perform the die filling simulations corresponds to the as-cast tensile specimens, as per ASTM B557 guidelines. The findings of the study include melt temperature distribution, solid fraction distribution during filling as well as during solidification, velocity distribution of the melt and surface defect concentration. Experimentation is performed to develop low superheat cast composite based on the numerically estimated optimum melt pouring temperature of 650°C. Mixture of irregular dendritic, polygonal and equiaxed shaped primary Mg₂Si grains are observed within the cast parts, whereas primary Al grains are found to be of dendritic morphology with occasional presence of spheroids. Marked improvements in microstructure and mechanical properties have been evidenced in the LSC composite compared to its conventional cast counterpart.

摘要

_{在这项研究中，采用计算流体动力学 (CFD) 模型来优化 Al-15 Mg 2} Si-4.5Si 复合材料在低过热度铸造 (LSC) 期间的熔体浇注温度。根据 ASTM B557 指南，考虑执行模具填充模拟的模具腔对应于铸态拉伸试样。研究结果包括熔体温度分布、填充期间和凝固期间的固体分数分布、熔体速度分布和表面缺陷浓度。基于数值估计的 650°C 最佳熔体浇注温度，进行了开发低过热铸造复合材料的实验。_{不规则树枝状、多边形和等轴状原生 Mg 2}的混合物在铸件内观察到 Si 晶粒，而初生 Al 晶粒被发现具有树枝状形态，偶尔会出现球状体。与传统的铸造对应物相比，LSC 复合材料在微观结构和机械性能方面有显着改善。