Microstructure, Mechanical, and Tribological Characteristics of Heat-Treated AA7075 Composite Reinforced With High-Entropy Alloy Particles

Abstract

This research examines the microstructural, mechanical, and tribological characteristics of an AA7075 alloy composite reinforced with high-entropy alloy (HEA) particulates, synthesized through advanced stir-squeeze casting techniques. To enhance grain refinement and optimize mechanical properties, the composite undergoes T6 heat treatment. Advanced characterization methods, including optical microscopy, scanning electron microscopy (SEM), and optical profilometry, are utilized to investigate microstructural features and worn surface morphology. Microstructural analysis reveals a homogeneous distribution of HEA particles within the AA7075 matrix, promoting a refined grain structure. Mechanical assessments indicate improvements in microhardness and compressive strength with the increasing HEA content. Tribological analysis shows that the wear-rate of the composite decreases with the increase in HEA particles, reaching a maximum reduction with 8 wt% HEA reinforcement. SEM observations of the worn surfaces reveal features such as pronounced grooves, adhesive wear, ploughing effects, wear debris, and microcracking.