Friction and wear behavior of WC/Ni cemented carbide tool material irradiated by high-intensity pulsed electron beam

The friction and wear behavior of high-intensity pulsed electron beam (HIPEB)-irradiated YN13 cemented carbide at energy density of 34 J/cm(2) and 10 pulses with pulse frequencies of 1 and 5 Hz were investigated in this work by dry sliding wear test against hardened GCr15 bearing steel at 98 N and 0.47 m/s. Surface characterization was conducted by using scanning electron microscope, surface profilometer, X-ray diffraction and Vickers microhardness tester. The dominant wear mechanisms were identified by the worn surface morphologies. The results indicated that an intense surface remelting and ablation/evaporation was induced by HIPEB irradiation with high pulsed frequency, which resulted in the surface roughening, WC phase transformation and improved tribological properties of the YN13 cemented carbide. The specific wear rate and friction coefficient decreased as pulsed frequency increased. When pulsed frequency increased to 5 Hz, they decreased to 53.5% and 70% for non-irradiated samples. The improvement in wear resistance and the significant friction reduction of irradiated samples with the increase in pulsed frequency should be ascribed to the roughening of surface, the refinement microstructure of remelting, and the decrease in irradiated defect in the remelted layer of irradiated YN13 cemented carbide. The main wear mechanism of irradiated YN13 cemented carbide/GCr15 bearing steel pairs was micro-cutting wear in the initial stage of dry sliding wear and abrasive wear with characteristics of Ni preferential removal and fallout of WC similar to the non-irradiated samples in the stable stage.