Low-cost and high-strength powder metallurgy Ti–Al–Mo–Fe alloy and its application

Abstract

Low-cost and high-performance are main research directions of structural titanium alloys. In this study, a two-phase structural Ti–5Al–3Mo–2Fe alloy was designed and prepared through elemental powder metallurgy (P/M) process, including cold isostatic processing, vacuum sintering, hot rolling and heat treatment. Results indicate that the P/M Ti–5Al–3Mo–2Fe alloy has a multi-phase microstructure with equiaxial primary α phase, needlelike secondary α phase and retained β phase. The room-temperature yield and ultimate strength reach to 1303 MPa and 1422 MPa, respectively, with a balanced elongation of 8.5%. At 400 °C, the alloy still has a high yield strength, ultimate strength and elongation of 850 MPa, 935 MPa and 17%, respectively. The Ti–5Al–3Mo–2Fe alloy was successfully processed into intake valves of automobile engine, which passed the engine test and meet the serving requirement.