Microstructure and mechanical properties of magnesium composites prepared by spark plasma sintering technology

Spark plasma sintering (SPS) technology was used to determine the appropriate conditions for SPS sintering of commercially pure magnesium as well as the magnesium alloy AZ31. It was found that the sintering temperatures of 585 °C and 552 °C were the most suitable sintering temperatures for the magnesium and the AZ31 alloy, respectively. Magnesium matrix and AZ31 alloy matrix composites reinforced with SiC particles were then successfully fabricated by the SPS method at sintering temperatures of 585 °C and 552 °C, respectively. A uniform distribution of SiC particles was observed along the boundary between matrix particles. The mechanical properties, i.e. hardness and tensile strength increased with increasing SiC content up to 10 wt%. However, when the SiC content was larger than 10 wt%, the tensile strength decreased due to the agglomeration of SiC particles. The agglomeration of SiC particles was found to lead to the degradation of the interfacial bonding strength between matrix and reinforcement.

► In the present study, the magnesium and AZ31 magnesium alloy matrix composites were fabricated with SiC particles by a spark plasma sintering method and the effects of sintering temperature and SiC content on microstructure and mechanical properties were investigated.
► It was found that the mechanical properties increased with increasing SiC content up to 10 wt%.
► The tensile strength decreased at higher percentage of SiC content due to the agglomeration of SiC particles.
► The agglomeration of SiC particles was found to lead to the degradation of the interfacial bonding strength between matrix and reinforcement.