Investigation on mechanical and tribological properties of AA6061/Gr composites for solar header pipes

Abstract

Solar header pipes desire light weight material with extensive mechanical and tribological property at high temperature. In this research work, an attempt was made to reinforce AA6061 aluminium alloy with Graphite particles through Stir Casting (SC) and Compo Casting (CC) technique for solar header pipes. The uniform dispersion of reinforcing particles over the matrix was confirmed through Scanning Electron Microscope (SEM). The tensile, hardness and wear experiments were performed on composites at elevated temperature. The wear experimental runs were designed using Taguchi mixed orthogonal array by varying temperature, applied load, sliding velocity, sliding distance and reinforcing weight percentage. The composites produced through CC method exhibit 3.8% and 2.7% higher hardness and tensile strength in comparison with SC. At elevated temperature of 300 C, the composites exhibit better wear resistance owing to the formation of Mechanical Mixed Layer (MML). The wear rate of composites at elevated temperature was three times higher than the room temperature owing to reduction in density and deformation of material. ANOVA table reveals that the most influencing process parameters was temperature followed by the load and percentage reinforcement. The worn surface morphology was analyzed using SEM. Because of the improved dispersion of reinforced particles, the composites generated by CC have higher mechanical and tribological qualities at elevated temperatures, and are considered as an alternative material for solar header pipes.