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The problem of poor fracture toughness of cemented carbide tool material is expected to be solved Release time：2020-08-13　　　　 Time to browse

　　The whisker added to cemented carbide material can absorb the energy of crack propagation, and the amount of absorption energy is determined by the state of the whisker and the matrix. The toughening mechanism of whisker is mainly shown as follows: (1) Whisker pulling out and toughening: when whisker is pulled out from matrix under the action of external load, part of external load energy is consumed due to interface friction, so as to achieve the purpose of toughening. The toughening effect is affected by whisker and interface sliding resistance. There must be sufficient binding force between the whisker and the matrix to enable the external load to be effectively delivered to the whisker, but the binding force must not be too large in order to maintain sufficient pulling length. (2) Crack deflection toughening: when the crack tip encounters a second phase whose elastic modulus is greater than that of the matrix, the crack will deviate from its original direction of advance and expand along the two-phase interface or within the matrix. Because the non-plane fracture of the crack has a larger fracture surface than the plane fracture, it can absorb more external energy and thus play a toughening role. The addition of whiskers or particles with high elastic modulus into the matrix can cause the crack deflection toughening mechanism. (3) Whisker bridge toughening: when the matrix is broken, the whisker can withstand the external load and play the role of bridge connection between the broken crack surface. The bridged whisker can produce a force to close the crack on the substrate and consume the external load to do work, thus improving the toughness of the material.