Strengthening and toughening mechanism of (W,Ti,Ta)C based cermet with the addition of c-BN@Al2O3.

Core-shell particles are considered to be one of the primary strengthening and toughening methods of cermet. In this study, a (W,Ti,Ta)C based cermet was prepared by vacuum hot pressing sintering technology with the addition of c-BN@Al 2 O 3 (Al 2 O 3 coated c-BN). Localized high residual stress around the core-shell particles causes the strengthening and toughening mechanism at short distances behind the crack tip, such as crack deflection, secondary cracks, crack branching, and grain pull-out, even at a small volume fraction of 10 vol%. Compared with cermet without Al 2 O 3 and c-BN, the flexural strength and fracture toughness of the cermet with 10 vol% c-BN@Al 2 O 3 are increased by 35.62% and 28.45%, reaching 1462 ± 49 MPa and 13.68 ± 0.51 MPa m1/2, respectively. [ABSTRACT FROM AUTHOR]