Investigation on the Effect of Cow Dung Ash/SiC Reinforcement and T6 Heat Treatment on the Microstructure, Mechanical, and Tribological Behaviors of Al7075 Matrix Composites

Abstract

Abstract. This study investigates the influence of sustainable [cow dung ash (CDA)] and ceramic (SiC) reinforcements on the microstructural, mechanical, and tribological characteristics of Al7075 synthesized through a two-stage stir casting process, along with the T6 heat treatment under varying temperatures and aging durations to optimize properties. The microstructural analysis employed optical microscopy (OM) and field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray spectroscopy (EDS), elemental mapping, and X-ray diffraction (XRD) techniques. OM and XRD revealed significant grain refinement and the presence of different phases, respectively, while FESEM confirmed uniform dispersion and integration of reinforcement particles within the matrix. Quantitative results indicate substantial enhancement in mechanical strength and tribological behavior driven by the synergistic effect of reinforcements and heat treatment. The T6 heat-treated (HT) sample containing equal weight fractions of reinforcements (2.5% CDA and 2.5% SiC) exhibited peak microhardness and compressive strength increments of 44.36% and 42.99%, respectively, relative to the as-cast Al7075. Worn surface morphology was analyzed using scanning electron microscopy (SEM) and optical profilometry, identifying wear debris, parallel grooves, adhesive wear, and plowing indicative of combined adhesive–abrasive wear mechanisms. Surface roughness (Ra) measurements showed a maximum reduction of 57.89% in a sample containing equal weight fractions of reinforcements, highlighting improved wear resistance.