Effect of MgO-TiO2-SiO2 additions on in-situ anisotropic grains growth and mechanical properties of corundum abrasive using pseudo-boehmite as raw material

Microcrystalline corundum abrasives with a duplex microstructure consisting of elongated anisotropic grains and fine equiaxed grains were fabricated via sol-gel processes using pseudo-boehmite as raw material. Elongated anisotropic grain, as a second phase reinforcement, significantly improved the fracture toughness and strength of samples. When the sample was doped 2 wt% MgO-TiO2-SiO2 additions with the molar ratio of 3:5:11, elongated anisotropic grains had the highest aspect ratio and were uniformly distributed among the fine equiaxed grains matrix. In addition, the sample obtained a maximum density above 3.92 g cm(-3), single particle compressive strength of 56.4 N and fracture toughness of 5.93 MPa m(1/2). The relationship between the microstructure and the mechanical properties of the abrasives was also discussed in detail. Moreover, toughening mechanism of elongated anisotropic grains was clearly explained by charactering crack propagation and fracture surfaces of samples.