Investigation of production of Al-Mg composites reinforced by SiC ve Al2O3 through powder metalurgy method

Metal matrix composite (MMC) materials are widely used in aerospace, marine, automotive and military industries expressing physical and mechanical properties such as low cost, low expansion coefficient, excellent dimensional stability, high corrosion resistance, high strength and high hardness. One of widely used composite materials is aluminum matrix composite (AMC). Commonly used techniques in the production of MMC materials are powder metallurgy, melt impregnation, pressure casting, mixing casting, ball milling, mechanical alloying and semi-solid mixing. In these methods, the metallurgy method is preferred because of the simplicity of the process, low cost and high mechanical properties. Various researches have been carried out on the production of MMCs for reinforcing materials such as Al2O3, TiC, MgO and SiC and continue to do so. In general studies, physical and mechanical behaviors of aluminum based composites produced by using particles at different sizes or proportions have been investigated. In this study, SiC and Al2O3 particles were added to Al-Mg matrix at different volume ratios by micro-sized powder metallurgy method and composite material was produced. As reinforcement, 1 μm SiC and Al2O3 particles were added to the Al-Mg matrix at different volume ratios. Al, Mg, SiC and Al2O3 powders were mixed for 1 day at a speed of 16 rpm to form a homogeneous dispersion. The mixed powders were pressed under 300 and 600 MPa pressure. Composite materials produced at different pressures were subjected to sintering for 30-60-90 min at temperatures of 300-400-5000C and allowed to cool in the oven. The properties such as density, porosity, microstructure and hardness of Al-Mg/SiC and Al-Mg/Al2O3 composites were investigated and characterized. Microstructure studies of the specimens were carried out by optical microscope, scanning electron microscope (SEM) and electron dispersion spectroscopy (EDX). Vickers hardness tests of the produced samples was done under 0.5 kg of load and 10 sec of dwell time. The highest porosity ratio for all test conditions was measured as 17,01795 in a 15% SiC reinforced Al-Mg composite produced at a pressing pressure of 300 MPa, a sintering temperature of 400 ° C, and a sintering time of 90 minutes. The lowest porosity ratio was measured as 5.526781 in a 30% SiC reinforced Al-Mg composite produced at 600 MPa pressing temperature, 400°C sintering temperature and 60 minutes sintering time. In their microstructure studies, a generally homogeneous microstructure was observed. In both types of reinforcement, the micro hardness of the composites increased as the content of reinforcing particles increased. The high reinforcement content caused the increase in the density of the composite.