Phase evolution in hot forging of dual phase titanium alloys: Experiments and numerical analysis

Modern aeronautical and aerospace industries must face the demanding challenge of reducing operational consumption and production costs coming from materials and labor. Current trend of engineering is oriented to meet both requirements increasing the use of materials characterized by high specific resistance as titanium alloys. Hot forging can be used to reduce the production costs of titanium components: forging in closed dies of billets or semi-finished forms, at different temperatures above or below the β-transus temperature, allows the production of complex shapes with limited amount of edge trim removal and machining rework after forging. Unfortunately, as far as Ti-6Al-4V titanium alloy is regarded, several material peculiarities have to be properly taken into account in order to produce defect free Ti-6Al-4V alloy components. In the paper, an experimental and numerical campaign, focused on a typical case study for aeronautical engines, is carried out. The aim of this research is to investigate the process mechanics and the causes for the final microstructure observed through micrographic analysis. Once set-up and tested against experimental loads, the model was used to predict phases distributions after both forging and cool down.