CONSOLIDATION OF Mg-SiC COMPOSITES BY SPARK PLASMA SINTERING

Mg based MMCs are increasingly used in automotive and aerospace applications. In this paper, Mg-SiC composites were obtained by the spark plasma sintering method. Various volume contents of SiC particles (5, 10, 15, 20 and 30 vol.%) were used. The samples have near full density, over 98%, and SEM observations confirmed the near full density of the sintered compacts. However, there was an optimum SiC content above which agglomeration of the SiC particles in the microstructure of the composites occurred. Moreover XRD analyses showed that besides Mg and alpha-SiC, beta-SiO2 (low-temperature beta-quartz) and Mg2Si phases are also present. The mechanical tests results demonstrate that the hardness and compressive strength of the obtained composites tend to increase with an increasing SiC volume content at the expense of compressive strain. The best results of hardness (111 HV0.5) and compressive strength (346 MPa) were obtained by the Mg-30% SiC composite.