Formations of wear-resistant extended layers by combined electron-ion-plasma treatment on the surface of aluminium

The study demonstrates that surface alloying of commercially pure A7 aluminum with titanium and copper through plasma-assisted vacuum arc deposition and electron beam irradiation provides the formation of Ti-Al and Cu-Al surface alloys whose hardness and wear resistance are several times greater than those of the initial material. The best result is attained with a Ti film 0.5 μm thick and a Cu film 1 μm thick after irradiation at a beam energy density of 10 J/cm ² and pulse duration of 50 μs. At these parameters, the microhardness of the Ti-Al system increases by a factor of ≈4.2 after 50 pulses, and its wear resistance by a factor of ≈2.3 after 100 pulses. The microhardness of the Cu-Al system increases ≈3.2 times and its wear resistance increases ≈1.5 times after 3 and 50 pulses, respectively. The increase in the hardness and wear resistance of the Ti-Al system owes to the formation of AlTi, Al ₃ Ti, Al ₂ Ti, TiAl ₃ , and Al ₅ Ti ₂ with a particle size no greater than 100 nm. The hardening phase in Cu-Al is Al ₂ Cu.