Effects of die shape and injection conditions proposed with numerical integration design on liquid segregation and mechanical properties in semi-solid die casting process

To solve the problem of reducing the weight of automobiles for the improvement of fuel efficiency and the protection of the environment, aluminum alloy parts have been substituted for steel parts. However, aluminum-alloy parts have inferior mechanical properties to those of steel parts. To improve the mechanical properties of aluminum-alloy parts, the semi-solid die casting process is used in the manufacture of automobile components. Semi-solid die casting has a different die structure from those of general die casting and squeeze casting. Because the oxide skin is produced during the reheating process will cause defects when it fills the die cavity, in semi-solid die casting the most important factors are the filling velocity, the area of the gate, and the position, size, the number of overflow. In this paper, a theoretically-proposed die structure for semi-solid die casting is verified by experiments, and the mechanical properties of the resultant parts are also presented. (c) 2006 Published by Elsevier B.V.