Effect of electron-beam treatment on the structure and properties of (B plus Cr) film deposited on a high-entropy alloy AlCrFeCoNi

The B + Cr film with a thickness of similar to 1 mu m was deposited by plasma-assisted RF sputtering on AlCrFeCoNi HEA of non-equiatomic composition prepared by WAAM. The subsequent treatment included electron beam irradiation of the surface with parameters as follows: energy density E-s=(20-40) J/cm(2), pulse duration 200 mu s, frequency 0.3 s(-1), number of pulses 3. It has been proved that microhardness increases by 2 times and wear resistance - by 5 times, whereas friction coefficient decreases by 1.3 times at an energy density E-s = 20 J/cm(2). High-speed crystallization of the surface layer leads to the formation of a cellular structure with cell sizes (150-200) nm. The increase in strength and tribological properties effected by electron beam treatment has been interpreted with the three factors in view: (1) the decreasing cell size, (2) formation of chromium and aluminum oxyborides, (3) formation of a HEA crystal lattice incorporating solid solution of boron.

Automated summary

A B + Cr film with a thickness of about 1 μm was deposited on AlCrFeCoNi HEA of non-equiatomic composition prepared by WAAM via plasma-assisted RF sputtering. Subsequent electron beam irradiation treatment resulted in a 2 times increase in microhardness, a 5 times increase in wear resistance, and a 1.3 times decrease in friction coefficient at an energy density of 20 J/cm(2). High-speed crystallization of the surface layer led to the formation of a cellular structure with cell sizes of (150-200) nm. The enhancement in strength and tribological properties can be explained by the decrease in cell size, the formation of chromium and aluminum oxyborides, and the formation of a HEA crystal lattice incorporating solid solution of boron.