Effect of heat treatment on wear behaviour of Al-7 wt%Si-X wt% Mg alloys

Abstract

Age-hardened as-cast aluminum alloys are being more and more used in the automobile industry because of their high strength, lightweight and low cost, which provide affordable improvement in fuel efficiency. In this current research, three different types of alloys are prepared by adding Mg (X = 1–5 wt%) with the Al-7 wt%Si master alloy. Prepared alloy samples were solution treated at a temperature of 535 °C for 4 h followed by water quenching. Then ageing is done at 165 °C with a span of 4 h. Wear tests were done by pin-on-disc wear testing instrument at normal load 10 N, 20 N, and 30 N, with varying sliding speed 200, 300, 400 rpm respectively for 5 min. Variation of wear with the applied load and sliding speed was studied from the experiment. It is noticed that decreases hardness value with the increasing content of Mg in Al-7 wt%Si+ (1–5 wt%) Mg alloy. Higher wear found with increasing normal load and sliding speed. Highest wear resistance (sliding wear) is seen in the Al-7 wt%Si-1 wt%Mg alloy sample. So heat treatment process improved the wear resistance. The worn surfaces are exhibited through a scanning electron microscope (SEM) in order to check the wear mechanism. Both the adhesive and abrasive wear mechanism is present from the study. Out of which abrasive wear mechanism is a more prominent one.