Mathematical Modeling of Complex-Shape Forming of Ultrafine-Grained Ti Alloy and Subsequent Deposition of Protective High-Entropy Coatings

Abstract— The paper reports on finite element simulation of extrusion of a complex-shaped billet from the ultrafine-grained Ti-6Al-4V alloy and vacuum-arc deposition of a protective coating based on the TiVZrCrAl high-entropy alloy. Temperature fields formed in the billet during extrusion are studied. Deformation heating and the necessary forming force are determined for the initial temperature-rate conditions. The strain rate distribution in the billet during extrusion is also analyzed. According to the obtained data, the chosen temperature-rate conditions allow using the ultrafine-grained titanium alloy as the initial billet without deteriorating its mechanical characteristics. Computer simulation of the coating deposition on the complex-shaped billet provides values of the temperature, chemical composition, and thickness of the high-entropy coating. Thus, the coating thickness varies within 6.5–7.5 μm, and the surface is heated during deposition to 368–597°C, which allows maintaining the ultrafine-grained structure in the alloy.