Effect of Aging Time on Characteristics of ADC12/SiC Composite with Addition of Sr Modifier and Al-5TiB Grain Refiner

An aluminium composite is developed as a light material with high strength for transportation application. Aluminium ADC 12 matrix was reinforced with SiC and added with Al-5TiB grain refiner and Sr modifier which is fabricated by stir-casting. The composites then were T6 treated for the various aging time from 2, 6, 10, 15 and 24 hours. The composites were characterized including tensile strength, impact resistance, hardness testing, wear resistance, density and porosity as well. The microstructural analysis to obtain the microstructure and phases changed after T6 using SEM-EDS and confirmed by XRD. Results show that T6 treatment has affected the morphology of primary and eutectic Mg₂Si, as well as precipitation of metastable β'-Mg₂Si from the aging process. T6 heat treatment has improved mechanical properties for all composites compared to as-cast composites. The highest ultimate tensile strength value and hardness are shown to be 144.5 MPa and 64.467 HRB after T6 for 6 hours at 170°C.