Effect of reheating temperature on the microstructure and tensile properties of SiCP/2024Al composite prepared by powder thixoforming

摘要

Powder thixoforming, a novel method for preparing and forming particle-reinforced metal-matrix composites has been proposed, and the effect of reheating temperature on the microstructure and tensile properties of a thixoforged SiCp/2024 Al-based composite was investigated. The results indicated that the temperature influences the liquid amount and microstructure compactness and the subsequent solidification behaviour during thixoforging. The best comprehensive tensile properties, ultimate tensile strength of 361 MPa, yield strength of 271 MPa and elongation of 4.2%, were obtained under reheating for 70 min at 898 K, which were 24 and 29% higher and 57% lower than those of 2024 Al matrix alloy thixoforged under the same conditions, respectively. The fracture mode of the composite varies from a mixture of intergranular and transgranular mechanisms to transgranular mechanism and intergranular mechanism as the temperature increases.