A high-oxygen strategy for strength-ductility synergy in powder metallurgy pure titanium via controlled TiO2 addition

In order to investigate the effects of interstitial oxygen on microstructural evolution and mechanical properties of PM pure titanium, near-net-shape composites with precisely controlled TiO 2 additions (0–1.6 wt%) were fabricated through vacuum sintering and subsequent hot forging at 1150 °C. Microstructural characterization reveals oxygen-induced grain refinement, reducing the average grain size from 18.90 μm to 7.29 μm. The Ti-0.8TiO 2 composition achieves optimal strength-ductility synergy, exhibiting an UTS of 916.1 MPa while retaining 23.1 % EL. Analysis of the ultimate tensile strength demonstrates that the cooperative effect of solid-solution and grain-refinement culminates at a critical oxygen equivalent of 0.6522 wt%. Quantitative assessment yields a UTS increment of 694.92 MPa per wt.% [O] eq , confirming the predominance of the oxygen solid-solution effect. These findings provide fundamental insights into interstitial strengthening phenomena and establish a quantitative framework for the rational design of high-performance titanium alloys through oxygen engineering.