Development of high performance Mg-Al2O3 composites containing Al2O3 in submicron length scale using microwave assisted rapid sintering

In the present study, magnesium composites reinforced with different volume fraction of submicron size Al2O3 particulates were synthesised using powder metallurgy technique incorporating an innovative microwave assisted rapid sintering technique. The sintered materials were subsequently hot extruded for characterisation in terms of microstructural, physical and mechanical properties. Microstructural characterisation results revealed a reasonably uniform distribution of Al2O3 particulates, minimal porosity and good matrix reinforcement interfacial integrity. The average coefficient of thermal expansion (CTE) value for Mg-Al2O3 composites was found to decrease with increasing amount of submicron Al2O3 particulates. Mechanical characterisation of the composites revealed an increase in hardness, elastic modulus, 0 center dot 2% YS and ultimate tensile strength (UTS) with the increase in amount of alumina particulates. Ductility exhibited the reverse trend. An attempt is made in the present study to correlate the effect of the presence of submicron alumina and its increasing amount with the microstructural, physical and mechanical properties of magnesium.