The effect of reinforcement ratio on the composite structure and mechanical properties in Al-MgO composites produced by the melt stirring method

Abstract

In this study, Al- MgO metal matrix composites (MMC) were produced with 5 %, 10 % and 15 % reinforcement- volume (R-V) ratios by the melt stirring method. In the production of composites 99.5 % pure Al was used as the matrix and MgO powders with the particle size of -105 μm were used as the reinforcement. For every R-V ratio; stirring was made at 500 rev/min at 750°C liquid matrix temperature for 4 minutes and the samples were cooled under normal atmosphere. Then hardness and fracture strengths of the samples were determined and their microstructures were evaluated by using Scanning Electron Microscope (SEM). In general, it was observed that the reinforcement exhibited a homogeneous distribution in horizontal direction. But there is a slight inhomogeneity in vertical direction. It was determined that the increase in the R-V ratio increased the porosity and also the hardness. As for the fracture strength, the highest strength was obtained with the 5 % MgO reinforced sample.