Effects of annealing treatment on the microstructure and mechanical properties of the AlN–SiC–TiB2 ceramic composites prepared by SHS–HIP

Abstract

Annealing treatments were carried out at different temperatures (600–1200°C) for various holding times (2–10h) to evaluate the microstructural and mechanical properties changes of the AlN–SiC–TiB2 ceramic composites prepared by SHS–HIP. The experimental results show that the annealing treatment is beneficial to improve the mechanical properties. In the meantime, the desolution of SiC-rich solid solution and precipitation of fine TiB2 grains occurred. Due to the precipitation strengthening by the SiC-rich solid solution and the grain boundary strengthening by fine TiB2 particles, the improvement of the mechanical properties was obvious with higher annealing temperatures and longer holding times. The highest HRA, bending strength and fracture toughness were 94.1, 517.5MPa and 5.79MPam1/2, respectively, after the annealing treatment at 1200°C for 10h.