Influence of thermodiffusion coatings on the mechanical properties of VT14 titanium alloy

We study the influence of various functional coatings with similar morphologies (oxide, nitride, carbonitride, and carboxide) formed by thermodiffusion saturation on the mechanical properties (short-term strength, plasticity, susceptibility to delayed fracture, fatigue life under the conditions of low-cycle and rotation bending) of thermally hardened VT14 high-strength (α +β) -titanium alloy (Ti–(3.5–6.3)%, Al–(2.5–3.8)%, Мо–(0.9–1.9)% V). It is shown that, for the analyzed morphology of the modified layer, the weakest influence on the mechanical properties is exerted by the two-component oxide coating and that the influence of all coatings strongly depends on the size factor (the ratio of the area of the metal occupied by the modified layer to the working section). The multicomponent coatings based on ternary interstitial compounds (carbonitrides and carboxides) give higher strength characteristics in combination with the comparable characteristics of the fatigue resistance and plasticity.