Effect of Heat Treatment on Mechanical Properties and Thermal Expansion of Al6063-SiC-Graphite, Molybdenum Disulfide Hybrid Composite

The effect of casting and T6 heat treatment at 540 °C for 3 h, quenching in water, heating to 180 °C for 4 h and cooling at room temperature on the mechanical properties and thermal expansion of Al6063 with reinforcement of 10 wt.% SiC/1 wt.% Y2O3/3 wt.% Graphite, 3 wt.% MoS2 was studied, comparing the properties of the material before and after treatment. The results of the tensile test found that the ultimate tensile stress (UTS) increased without reinforcement applied but decreased the elongation at breaking point (%El). This contrasts with the reinforcement applied group, which showed an increase in the UTS and %EL by 4.1% and 32.5% in Gr, 10.5% and 44.9% in MoS2, respectively. Meanwhile, the UTS and %EL increased by 23.5% and 26.98% in Gr, 22.7% and 15.0% in MoS2, respectively, after the T6. Cracking analysis in the treatment without the addition of reinforcement showed ductile and brittle fracture after casting, similar to the effects of being treated by T6, which was characterized by brittle fracture. This was contrary to the reinforcement-added treatment, which was characterized by ductile fracture before and after treatment. The thermal expansion coefficient (CTE) after treatment without reinforcement applied was reduced, while no significant difference was seen with reinforcement applied.