Thermally stable microstructure and mechanical properties of graphene reinforced aluminum matrix composites at elevated temperature
Min Li, Yufei Wang, Haiyan Gao, Jun Wang, Baode Sun
Abstract
Heat resistant Al alloys with thermally stable microstructure and mechanical properties at elevated temperature is desperately required in various engineering applications. In this study, thermally mechanical behaviors of graphene nanoplatelets (GNPs) reinforced Al matrix composites were investigated by annealing and tensile tests at elevated temperature. The hardness retention of the GNPs/Al composites kept more than 94% when annealing temperature was lower 500 °C and reached about 88% after annealing at 600 °C (0.91 Tm), showing a relatively higher durable temperature than most traditional heat resistance Al alloys. Microstructure observations revealed that Al/Al2O3/GNPs interface was stable up to 600 °C, which was considered to be effective barriers to grain boundary migration of Al matrix. Tensile test carried at 300 °C showed that strength of GNPs/Al composites retained 111 MPa, which is 120% higher than that of pure Al (50 MPa). GNPs/Al composites kept higher tensile strength even tested at 500 °C. Enhanced grain boundary stability with introducing GNPs in the interface and effective load transfer from Al matrix to the GNPs synergistically promoted high temperature tensile strength. The super thermal stability of GNPs/Al composites showed promising prospects in high temperature applications.