The Numerical Simulation Of Rheo-diecasting Process Of Filling And Solidification Of Liquid Magnesium And Semisolid Magnesium Alloy

Owing to magnesium alloy is the lightest structural metal in the world, it's a very importance value to reduce automobile weight and oil consumption and environment pollution even to improve the operationality of the automobile. Now die casting is the mostly technology of magnesium alloy processing, but the traditional die casting technique is same for magnesium to other alloys, the same problems for gas in die cavity and the gas produced by coating mixture can't eject properly. Because under the high pressure the gas will be dissolved or formed many micro pores diffusing into the die casting. These defect can be avoided and the inherent quality will be improved by die casting technology of magnesium alloy rheocasting or thixo casting, but the cavity filling method and cavity filling capability and other methods of magnesium alloy die casting aren't understood totally, it's desiderate to do some researches in these field. By the aided of numerical simulation technique we can not only accurate picture the cavity filling process also can predict moulding fault among the die casting et al. the numerical simulation of cavity filling and graining process is the hard core in using the computer technology in foundery practice, also it's a leading edge field for widening and promoting the development of casting technology, and inaugurating a new phases to improve and ensure the cast product quality.Base on the above consideration, my paper analysis a casting of magnesium alloy and semisolid magnesium alloy materials named middle shaft plug screw, having analyzed the process about Newtonian liquid and semisolid liquid of magnesium alloy by the numerical simulation technology. Among the analysis, I have analyzed mostly about the velocity vector magnitude , direction of each fluid, the fluidal distinction of each fluid when filling the die cavity, the transfer situation of fluid body internal pressure, the variety of velocity and pressure among die cavity internal nodes in the filling process, the variety about die casting solidification, the solidification fraction when the die casting freezing, and the position, the size of the shrinkage cavity and the shrinkage porosity are all be calculated too.The result of my paper indicated that compare to the Newtonian fluid alloy the semisolid alloy has a stable filling process, little splashing, the lightening of turbulence, whirlpool and the gas involution et al. the heat shock of the die will be lightened and the service life of die will be improved by the lower filling temperature.