Investigation of mechanical and tribological behaviour of graphene nanoplatelet reinforced ZE10 magnesium alloy

Abstract

Since graphene was discovered, it has increased the hopes of improving and widening the usage areas of metal matrix composites with its unique mechanical properties. Graphene nanoplatelets (GNPs) was reinforced into the matrix in this study. The added GNPs have approximately 10-20 nm thickness and 14µm diameter. 0, 0.25, 0.5, and 1.0wt.%GNPs were incorporated in the matrix, which is ZE10 Mg alloy. Compared to pure magnesium, ZE10 alloy has better ductility, formability, creep resistance, and corrosion resistance thanks to the rare earth elements. The stir casting method is demanded in industry owing to its suitability for making products complexshaped in large sizes. The combination of stir casting and ultrasonic processing was employed. Due to the high surface energy of nanosized GNP reinforcement, high energy mixing is required effectively to ensure homogeneous distributions. Therefore, ultrasonic processing was applied along with stir casting. This study aims to investigate the microstructure, mechanical properties, and wear behavior at various temperatures of ZE10 alloy with reinforced GNP. The microstructure examination, ball-on-disc, hardness, and tensile tests were performed on the cast reference alloy without GNP and composites. Ball-on-disc and hardness tests were performed at room temperature, 100 􀂃C and 200 􀂃C. It was observed that obtaining a homogeneous distribution became more difficult with the increased GNP content in the optical microscope images. The composite with 0.25 wt. %GNP content has the smallest grain structure compared to composites with different content of GNP (0.5 and 1.0 wt.%GNP). It was also observed that adding 0.25 wt. % GNP improved the wear and hardness values 8,1% and 22% at room temperature, respectively. Adhesive and abrasive mechanisms were proposed to be the principal wear mechanisms in consequence of the existence of delicate furrows, and plowing marks.