Structure, Elemental, and Phase Composition of the Surface Alloy Ti–Al–V–Ag Synthesized by the Combined Action of Ion-Plasma Flows

Abstract

The formation of surface Ti–Ag–Al–V alloy was carried out by compression plasma flows impact on Ti–6Al–4V titanium alloy preliminary coated by silver. The coating was deposited on the sample by the electron beam technique. The thickness of the coating was approximately 2 μm. The treatment of the system samples was carried out by three pulses of compression plasma flows in a nitrogen atmosphere (energy density absorbed by the surface varied from 26 to 43 J/cm2 per pulse). The phase and elemental composition, structure, surface roughness, and microhardness were investigated. It has been established that the action of compression plasma flows on Ag/Ti–6Al–4V system results in the formation of TiAg, Ag, and δ-TiN in the surface alloyed layer. Increase of the energy absorbed by the surface during plasma impact (26–43 J/cm2) led to a decrease in Ag concentration (20.0–6.9 wt %) in the analyzed layer. The change of phase composition and structure results in modification of the microhardness. A microhardness increase up to 4.8 GPa (1.3 times in comparison with initial Ti–6Al–4V alloy) was found after compression plasma flows’ treatment at 43 J/cm2.