Texturing effect of crater-like cavities induced by high-current pulsed electron beam (HCPEB) irradiation

High-current pulsed electron beam (HCPEB) irradiation commonly induces crater-like cavities on irradiated surfaces, making them tribologically resemble textured ones. However, the effect of crater-like cavities on the lubricated tribological properties of HCPEB-treated surfaces has not been reported in the literature. This work was aimed at exploring the potential texturing effect of the crater-like cavities. Surfaces with continuous and uniform crater-like cavities were prepared through HCPEB irradiating a 400-nm thick Ta coating that was pre-deposited on polished M50 steel. Their boundary tribological behaviors were studied while sliding in chemically inert, low-viscosity hydrocarbon fuel JP-10 against a Si₃N₄ ball under 2.0-4.0 GPa. At 2.0 GPa, the coefficient of friction (COF) and wear rate of the polished M50 steel were above 0.16 on average, with large fluctuation, and 1.49 × 10^-5 mm³/N·m(a rectangle-like profile of 167.9 μm× 8.1 μm), respectively. In comparison, the HCPEB-treated Ta coating had a stable, marginally fluctuant COF of 0.11 and a near-zero wear rate. Under other higher loads, the HCPEB-treated Ta coating still exhibited a stable COF of 0.11 on average with small fluctuation, and its wear track width was only half that of the M50 steel. The analysis of the wear topographies indicates that the substantial reduction in both the COF and wear rate was mainly due to the texturing effect originating from the crater-like cavities.