Microstructural, mechanical and wear behaviour of AA7075/ZrSiO4 surface composite developed via multi pass friction stir processing

Abstract

ABSTRACT The microstructural, mechanical, and wear behaviour of the ZrSiO4-reinforced AA7075 surface composites fabricated through friction stir processing was analysed. The microstructure of the friction stir processed surface composite shows refined grain 52 μm, 20 μm and 5 μm after 1, 2 and 3 FSP pass which also leads to the uniform dispersion of reinforced ZrSiO4 particles in the A7075 surface as revealed by SEM, EDS, and XRD. The microhardness and tensile strength of the FSP surface composite were significantly improved by 35% and 54%, respectively, with the effect of ZrSiO4 particles, after six passes as compared to the substrate material. The slurry abrasive wear resistance of the surface composite after six FSP passes increased to 95% as compared to the A7075 substrate material. Similarly, the slurry erosive wear resistance was improved with increasing slurry rotating speed, but as slurry concentration increased at six passes, the wear rate decreased further due to self-colloids occurring between the slurry particles. Hence, slurry erosive wear resistance was increased by up to 220% as compared to substrate material. Hence, the novel fabrication of friction stir processed surface composite will be very beneficial for aerospace and marine structural components and the fabrication process is very robust and cost-efficient.