Preparation of in-situ growth TaC whiskers toughening Al2O3 ceramic matrix composite

An in-situ growth TaC whiskers toughening Al2O3 ceramic matrix composite was prepared by two steps, which were in-situ synthesis of TaC whiskers in Al2O3 matrix powder and hot pressing of the composite respectively. The preparation process, microstructure and toughening mechanisms of the composite were investigated in detail. TaC whiskers with a diameter of 0.2–1 μm and an aspect ratio of 10–30 were in-situ synthesized in the Al2O3 matrix powder by a carbothermal reduction technique. The flexural strength, fracture toughness and Vickers hardness of the composite were 638 MPa, 6.5 MPa·m1/2 and 17.4 GPa respectively. An improvement of the mechanical properties was ascribed to the TaC particles and whiskers which induced the toughening effects such as the crack deflection, interface debonding, whisker fracture and whisker pullout. The fracture mode of the composite was the combination of transgranular fracture and intergranular fracture which improved the mechanical properties of the composite.

An in-situ growth TaC whiskers toughening Al2O3 ceramic matrix composite was prepared. The main toughening mechanisms were crack deflection, interface debonding, whisker fracture and whisker pullout. The fracture mode of the composite was the combination of transgranular fracture and intergranular fracture.Figure optionsDownload as PowerPoint slideHighlights
► In-situ growth TaC whiskers toughening Al2O3 matrix composite was prepared.
► The mechanical properties were improved by TaC particles and whiskers.
► The toughening mechanisms were crack deflection, whisker pullout, et al.
► The fracture modes were transgranular fracture and intergranular fracture.