Dry Sliding Wear Mechanism of WC-13Ni Hard Alloy Irradiated by High-Intensity Pulsed Electron Beam

The wear properties and wear mechanism of WC-13% Ni hard alloy irradiated by high-intensity pulsed electron beam (HIPEB) at energy density of 34 J/cm(2) with pulse numbers of 1-10 were investigated by dry sliding wear tests. The phase structure, cross-sectional microstructure and microhardness-depth profiles of the irradiated WC-13Ni hard alloy were examined by using X-ray diffractometer, scanning electron microscopy and Vickers testers, respectively. It was found that HIPEB irradiation induced surface remelting and preferentially ablation of Ni binder phase, resulting in the formation of a modified layer composed of remelted top layer accompany with WC phase transformation and graphite phase precipitation, and shock hardening layer. The specific wear rate of the irradiated samples decreased with the increasing pulse number and reached a minimum value of 3.8 x 10(-7) mm(3)/N m with 10 pulses, only for 32% of the non-irradiated samples. The wear mechanism of surface remelting top layer on the irradiated samples was a homogenous microabrasion wear, which was attributed to the surface remelting and phase transformation, and the wear of the shock hardening layer involved preferential removal of Ni binder phase and detachment of WC grains, but it was restrained by strengthening of Ni binder phase from the deep hardening of HIPEB irradiation.