Study on microstructure, mechanical and wear behavior of AA7075/hBN composites fabricated via liquid metallurgy

Abstract

These research works investigate microstructure, mechanical strength and wear characteristics of AA7075/ hBN composites. AA7075/hBN composites are manufactured through two- step stir casting techniques with varying (0–7.5 wt%) hBN particles and subjected to T6 heat treatment. The optical microscopy of the composites shows that the reinforcement particles were distributed finely and with few cluster formations. The results stated that improved hardness on AA7075/5.0 wt% hBN composite as compared to as-cast alloy. The wear behaviour of alloy and composites are analysed on a pin-on-disc tribometer with varying applied loads of (20–60 N), a sliding velocity of 2.0 m/s, and a sliding distance of 3000 m, with EN31 steel as a counterpart. The wear rate and coefficient of friction of the composite reduced as the hBN particle concentration increased. A scanning electron microscope (SEM) is used to analyses the wear process on the worn surface, its reveals abrasion, oxide layer, and delamination as wear mechanisms under varying applied load conditions.