Porous and non-porous alumina reinforced magnesium matrix composite through microwave and spark plasma sintering processes

In this study, Alumina reinforced Magnesium Matrix Composites have been prepared by two different sintering method: microwave and spark plasma sintering (SPS) processes. 5 wt% alumina whisker was blended with magnesium powders in ethanol media for 10 min. The sintering temperatures in the spark plasma and microwave furnace were at 420° and 700 °C, respectively. Thermodynamic investigation and XRD results revealed the formation of MgO, Mg2Al3 compounds in both sintered composites. However, microwave sintering led to form a porous composite (53.1% of theoretical density) while SPS resulted to formation of a fully dense composite. The mechanical examinations showed higher bending strength (163 ± 10 MPa) and micro-hardness (101 ± 11 Vickers) of SPS samples rather than microwave samples as it expected. By using two different sintering methods (pressure-less and pressure-assisted) and controlling processing parameters, the porosity of the final products can be changed from porous to fully dense composites.