Effect of Magnesium on Hardness and Microstructure of Metal Matrix Composite Al.6061/(Al2O3)p Produced by Stir Casting Route

Abstract

Al.6061/Al2O3 metal matrix composites (MMCs) has been fabricated by stir casting. The MMCs were prepared by addition of Al2O3 particulates reinfoced with varios Mg content, 8, 10, 15 %wt Mg. Al.6061/Al2O3 composites with different Mg contents were successfully fabricated by stirring technique under optimum processing conditions. Effects of Mg content on microstructure and hardness were studied by Scanning Electron Microscopy (SEM)-EDX, SEM-Xray Map, XRD and Rockwell Hardness. The results indicate that Al2O3 particles disperse homogeneously in Al matrix and interfacial reaction between Al matrix and Al2O3 particles is effectively controlled. Distribution of Al2O3 reinforcement and interfacial bonding were improved by adding Mg. Additionally, the hardness of composites were remarkably improved with the Mg. The highest hardness of composites obtained in 15%wt Mg with a value of 55 HRB.