In die-casting simulation, it is very important to take into account back pressure and the flow of air remaining inside the mold. However, two-fluid flow simulation requires considerable calculation time, because of the difficulties in the convergence of calculation and the conservation of mass balance. In the present study, we propose an implicit FEM algorithm applying the Semi Laglangean Galerkin Method (SLG) for the advection equation of the VOF function to realize computational efficiency and stabilization. This numerical method was developed based on tetra mesh, which can be used to build analytical models automatically. Furthermore, we adopted a VOF function transformation technique to preserve the mass conservation and keep the interface sharp. As a bench mark test problem of the advection equation for this numerical method, we applied the present scheme to the rectangle rotation problem.
  We confirmed that the sharp interface between liquid and air was preserved after one rotation of the rectangle. Furthermore, we applied the present scheme to the dam break problem with an obstacle. Use of the VOF function transformation technique maintained mass conservation error within 0.15%, and the simulation could be performed with a large time step interval by applying the implicit method. Compared with experimental data, the characteristic behavior of the interface could be determined using the present scheme. Finally, we applied this scheme to squeeze casting simulation, and the numerical results showed good qualitative agreement with experimental data.

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  In order to clarify the effects of strontium and phosphorus on eutectic cell count and morphology in high purity Al-7% Si alloys, the quench technique was applied, and eutectic cells were observed on the contact surface with the mold. In addition, the eutectic solidification starting temperature was measured. The results are as follows. The eutectic solidification starting temperature decreases with the addition of strontium. Strontium does not change the number of eutectic cells of the alloy without phosphorus, but decreases the number of eutectic cells of the alloy with phosphorus. Protrusions were observed on the solid-liquid interface of the alloy without strontium, whose shape resembled the leaf veins of plants. On the other hand, the solid-liquid interface of alloys added with strontium was smooth. The curvature of the eutectic silicon with the addition of strontium may be due to the formation of strontium-rich, low eutectic temperature liquidus film in front of the eutectic solid-liquid interface.

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