THE FORMATION OF SURFACE Ti-Al-V-Cu ALLOY BY COMBINED ION-PLASMA TREATMENT

Abstract

In this work, surface Ti-Cu-Al-V alloy was synthesized by compression plasma flows impact on Ti-6Al-4V titanium alloy preliminarily coated by copper. The treatment of Cu/Ti-6Al-4V samples was carried out by three pulses of compression plasma flows generated in the nitrogen atmosphere (energy density absorbed by the surface was varied in the range of 26–43 J/cm2 per pulse). The phase and elemental composition, structure, microhardness and friction coefficient of the formed surface alloy were investigated. It has been established that plasma treatment resulted in the formation of α-Ti solid solution containing alloying elements in the surface layer and δ-TiN on the surface. An increase of the energy absorbed by the surface during plasma impact led to a decrease of Cu concentration (2.7–0.5 wt %) in the analyzed layer. The surface alloy was characterized by a uniform distribution of Ti, Al, and V atoms in contrast to the distribution of these elements on the surface of the untreated Ti-6Al-4V alloy. The microhardness increase up to 4.7 GPa (1.3 times higher in comparison with initial Ti-6Al-4V alloy) was found after compression plasma flows treatment at 43 J/cm2. Tribological tests showed that the minimal friction coefficient (0.13) was observed after treatment at the absorbed energy density of 26 J/cm2.