Evaluation of mechanical and corrosion properties of AZ91-GNP nanocomposites fabricated using the SMART/MA process

Abstract

Mg and its alloys are lightweight metallic materials with a low density and high specific strength. The Mg alloy AZ91 is used as a lightweight structural material in automobiles because of its high mechanical strength and corrosion resistance. In Mg-based nanocomposites, wherein graphene nanoplatelets (GNPs) are added as reinforcement materials to the AZ91 matrix, severe agglomeration occurs in the process of mixing the GNPs and Mg alloy powders owing to extensive van der Waals bonds between the GNP layers. This agglomeration of GNPs in the Mg alloy acts as a crack initiation site and lowers the mechanical properties and corrosion resistance of the alloy. In this study, a double-powder mixing process called SMART/MA is developed to inhibit GNP agglomeration. This process produces an AZ91-based composite with a few layers of GNP evenly dispersed throughout the matrix, which improves its mechanical properties and corrosion resistance.