Effect of SiC Content on the Microstructure and Properties of Zr2Al4C5/SiC Composites in situ Fabricated by Spark Plasma Sintering

摘要

Zr2Al4C5/SiC composite ceramics were successfully fabricated from the powder mixture of Zr, Al, C and SiC by spark plasma sintering method. The composition-dependent densification, phase evolution, micro structure and mechanical properties of the composite ceramics were studied. With increasing the SiC content in the starting powder mixture, the densification behavior of sintered samples was promoted. It is found that the as-sintered products are mainly composed of Zr2Al4C5 matrix and SiC reinforcement, and the fine SiC particles tend to disperse on the matrix grain boundaries. Besides, the addition of SiC particles can evidently hinder the coarsening of Zr2Al4C5 grains. Both the Vickers hardness and Young's modulus of composites ceramics gradually increase as increasing the SiC content. The fracture toughness of the composites decreases first then increases with the increase in the SiC and the Zr2Al4C5/30vol%SiC sample possesses the maximum value of 4.4MPa-m1/2.