Mechanical and tribological properties of AA7075-T6 metal matrix composite reinforced with ceramic particles and aloevera ash via Friction stir processing

Abstract

Mechanical and wear properties of AA7075-T6 reinforced with SiC and Aloevera ash, fabricated using Friction stir processing (FSP) are investigated in this study. Due to less density, easy availability, and cost-effectiveness, aloevera ash is considered as one of the reinforcements. FSP is done using a square tool pin profile, at different tool rotational speeds. To study wear behaviour, pin on disc test is carried out on High Temperature Rotary Tribometer at 20N, 30N and 40N applied load. Wear increases on increasing the applied load and at 20N load Al+SiC/Aloevera ash composite, processed at 600 tool rpm gave the best results due to the formation of oxide tribolayer. At 30N and 40N applied load Al+SiC composite, processed at 900 tool rpm showed the least wear because of proper scattering of ceramic particles due to high tool rotational speed. Coefficient of friction increases on increasing the applied load and all fabricated composite samples showed a lesser coefficient of friction than the base metal. Microhardness, ductility and Ultimate tensile strength increases on the addition of reinforcement and had a direct relation with tool rpm. Wear morphology was analysed using Scanning Electron Microscope (SEM). Energy Dispersive Spectroscopy (EDS) analysis after wear shows the presence of C, Fe, O, Mg, Zn, Si, Al elements and confirms the formation of an oxide layer which is responsible for decreasing wear loss.