Pulsed electron-beam treatment of WC–TiC–Co hard-alloy cutting tools: wear resistance and microstructural evolution

The mechanisms for changes in the structure-phase state, microhardness, and wear resistance have been investigated for carbide inserts made of type T15K6 (WC–15TiC–6Co) hard alloy, irradiated with a low-energy (20–30 keV, high-current (∼102 A cm−2) electron beam of duration 2.5 μs. Using transmission electron microscopy, it has been established that the pulsed melting of the near-surface (∼1 μm) layer results in the formation of a subgrain structure in the binding phase, segregation of nanosized carbide particles in the near-boundary regions, and the allotropic transformation of WC. The irradiation increases by about three times the durability of the inserts at elevated cutting rates for steels. The increase in durability is associated with the efficient hardening of the Co binder immediately on irradiation and with its high thermal stability being retained in the process of cutting due to the stability of the dislocation substructure provided by second-phase segregates.