Papers by Author: Tao Zhang

Abstract: During Thixomolding process, solid phase fraction decreased with the injection velocity increasing. Meanwhile, the solid phase morphology changed from irregular dendrite to near spherical. Friction heat produced by high speed melt flow could cause partial melt of solid phase, and the morphology of solid phase would form into globular. The dendritic solid phase can be broken by high speed melt flow under the condition of injection velocity higher than 2.0m/s.

Abstract: Magnesium alloy is the lightest metal that can be used as structural material at present. As a novel forming process for magnesium alloys, thixomolding can result in a product with few defects and superior dimensional accuracy, and it is suited to manufacture the thin wall products especially. In this paper, the samples of mobile phone housing were fabricated by 220Tons thixomolding machine made by Japan Steel Works. The effects of barrel temperature, screw rotate rate and injection velocity on the mechanical properties were studied. The relationship between process parameters and mechanical properties was investigated. The results show that the effects of barrel temperature and screw rotate rate on the mechanical properties can be divided to low temperature and high temperature stage. The high tensile strength are corresponding to the best injection velocity.