Effects of Reheating Duration on the Microstructures and Tensile Properties of Thixoforged In Situ Mg2Sip/AM60B Composites

The influences of reheating duration on microstructures and tensile properties of thixoforged in situ Mg2Sip/ AM60B composites have been investigated. The results indicate that the reheating time affects the volume fraction, composition and distribution of the liquid phase, the evolution of the liquid pools within the primary particles, and the morphology and distribution of the Mg2Si particles of the semisolid feedstock. These changes then affect the subsequent solidification behavior and deformation mechanism during thixoforging, which are responsible for the resulting microstructure and tensile properties. Mg2Si particles play a strengthening role for the matrix through the load transfer mechanism. The appropriate reheating time is 60 min at 600 degrees C when the mold preheating temperature is at 300 degrees C. The ultimate tensile strength and elongation of the resulting composite are up to 209 MPa and 11.9%, respectively.