Optimization on hardening process parameters of alumnium alloy 7075 based composites using gra approach

Abstract

Aluminium Metal Matrix Composites (AMMCs) are the essential need for applications such as aerospace, aircraft, marine, transport and automobiles due to their best mechanical, corrosion and tribological behaviour. In this research, Alumnium alloy 7075 is chosen for matrix material because of its much more need of mechanical, corrosion and tribological properties enhancement. The nano zirconium di oxide (ZrO2) is chosen for reinforcement to fulfil the properties requirement of AA7075 for various applications. The AA7075/wt. % Zr02 (x= 0, 5, 10, 15 and 20) composites are prepared by stir casting route. The fabricated composites are subjected to tensile strength and density test to determine the best combination of AA8009 based composites. The best combination of AA7075 based composites is subjected to EDAX and SEM test to determine the presence of elements of reinforcement and matrix material. The stir casted AA7075 based composites are further subjected to hardening under different conditions to enhance their required properties. The input parameters of hardening are age hardening temperature, hardening duration and cooling environment. The chosen response parameters are micro hardness and wear loss. The micro hardness and wear resistance of composites are determined by employing tensile Vickers hardness tester and pin on disc equipment. The optimization is done by using Grey Relational Analysis (GRA). The optimized age hardening process parameters are hardening temperature (400°C), hardening duration (270 minutes) and cooling environment (Furnace cooling). The obtained higher micro hardness and lower wear loss of confirmation test combination specimen is 138 HV and 27 mg respectively.