Influence of Multiwall Carbon Nanotubes (MWCNT) on Wear and Coefficient of Friction of Aluminium (Al 7075) Metal Matrix Composite

Abstract

Metal matrix composites of Aluminium alloy are used extensively in the domain of aerospace and automobile due to their superior properties as compared to that of the base alloy. With addition of dispersoids such as carbides, graphene and nitrides, a more advanced and hybrid metal matrix composite can be prepared and characterized. This report aims to study the tribological properties of aluminium metal matrix composite by adding multiwall carbon nanotubes (MWCNT) as reinforcement. Al 7075 alloy of T6 grade was used as the base matrix which was reinforced with multiwall carbon nanotubes having weight percentages of 0.25, 0.5 and 0.75. The specimens were fabricated using stir casting technique at suitable conditions. The wear properties of the metal matrix composite were investigated with the aid of pin on disc apparatus by conducting dry sliding wear test. Testing parameters of applied load (N), sliding time (min), and sliding speed (rpm) were varied using Taguchi’s L9 orthogonal array. From the results thus obtained, it can be inferred that the increase in percentage of reinforcement decreases the wear rate of the composite. This increase in resistance is observed up to addition of 0.5 weight percentage of MWCNT. With increase in addition of MWCNT from 0.5 weight percentage to 0.75, the wear resistance of the composite remains same, but under severe testing conditions, it is seen that the wear resistance of the metal matrix composite reduces when compared with the base matrix.