Abstract
Abstract
The characteristics of the thixoforming process can decrease liquid segregation because of the improvement in fluidity in a globular microstructure state and can utilize flow without an air entrapment. Therefore, in order to obtain the sound parts of metal matrix composites by using the thixoforming process, which has a coexisting solidus-liquidus phase, it is very important to design a die shape property and to obtain the fabrication conditions that affect the uniformity of the solid fraction on the unfilling state and various defects throughout the fabricated parts. The die designs and fabrication conditions used to obtain a good piston part were proposed for the thixoforging process of metal matrix composites. When reheated, metal matrix composite billets were transferred to the closed die gate and thixoforging was carried out under the various pressures (60, 80, 100 MPa) with a controlled forging speed. The mechanical properties, such as hardness and tensile strength, used for the specimens machined by thixoforged parts have been investigated after T6 heat treatment.