Effect of Fe Content and Post-Heat Treatment on Mechanical and Corrosion Properties of Ti-5Mo-xFe (x = 2, 4 wt%) Alloys Fabricated by Hydrogenation–Dehydrogenation Process

Cost-effective β-titanium alloys were developed via the hydrogenation–dehydrogenation (HDH) process using low-cost β-stabilizers Mo and Fe. Ti-5Mo-xFe (x = 2, 4 wt%) alloys were fabricated by powder metallurgy and subjected to six post-heat treatment conditions to reduce porosity and improve properties. The as-sintered alloys exhibited high porosity (15–20%), which adversely affected mechanical and corrosion performance. Heat treatment above the β-transus significantly reduced porosity, with Ti-5Mo-4Fe treated at 900 °C for 2 h showing the greatest reduction. Microstructures evolved from α + β lamellar Widmanstätten to equiaxed β with TiFe precipitates. Increased Fe content and heat-treatment temperature enhanced strength, while TiFe precipitates degraded corrosion resistance. Thus, optimized post-heat treatment improves strength and corrosion performance, although Fe content must be controlled.