Representative volume element (RVE) based FEA investigation on the plastic flow behaviour of friction-stir processed AA7075/Si3N4composite under constrained deformation conditions

Abstract

In the present investigation, the Si3N4reinforced (with a weight percentage of 2.5%, 5% and 7.5%) AA7075-based metal matrix composite has been developed by friction-stir processing. Further, a micro-mechanical representative volume element (RVE)-based finite element analysis (FEA) model has been developed for the evaluation of mechanical properties and plastic flow behaviour of developed composite material in uniaxial conditions. Moreover, a macro-mechanical-based static indentation finite element model has been developed for predicting the plastic flow behaviour, Meyer's hardness, constraint factor (CF) and lip height around indentation as a function of average strain under constrained conditions. The results revealed that Meyer's hardness, yield strength, tensile strength and lip height were increased with the increase in Si3N4reinforced weight percentage. Further, the lip height was inversely proportional to the strain hardening exponent. It has been also observed that the CF of all three developed composite material compositions increased with the increase in average strain ( εavg) up to the transition strain ( εtr) only, after that its value was constant with further increase in average strain ( εavg).