Due to the poor fracture toughness of cemented carbide tool materials, it is difficult to be applied to some machining occasions with high requirements for tool toughness (such as micro-deep hole drilling, etc.). An effective method to solve this problem is to use whisker toughening and reinforcing technology.

The energy of crack propagation can be absorbed by whisker added into cemented carbide material, and the amount of energy absorbed is determined by the bonding state between whisker and matrix. The main mechanisms of whisker toughening are as follows: (1) Whisker pulling out toughening: When the whisker is pulled out of the matrix under external load, part of the external load energy is consumed due to interface friction to achieve the purpose of toughening. The toughening effect is affected by the sliding resistance between the whisker and the interface. There must be enough binding force between the whisker and the matrix interface so that the external load can be effectively transferred to the whisker, but the binding force should not be too large to maintain sufficient pull-out length. (2) Crack deflection toughening: When the crack tip encounters the second phase whose elastic modulus is greater than that of the matrix, the crack will deviate from the original direction and expand along the interface of the two phases or in the matrix. Since the non-plane fracture of a crack has a larger fracture surface than the plane fracture, it can absorb more external energy and thus play a role in toughening. The mechanism of crack deflection and toughening can be induced by adding whiskers or particles with high elastic modulus into the matrix. (3) Whisker bridging toughening: When the matrix is fractured, the whisker can withstand the external load and act as a bridge between the broken crack surfaces. The bridged whisker can produce a force to close the crack on the matrix and consume the external load to do work, thus improving the toughness of the material.