Developing pure titanium with 1 GPa tensile strength and 24 % elongation by interstitial oxygen doping

Interstitial oxygen in the octahedral sites, could strengthen titanium (Ti) and its alloys efficiently. However, oxygen tends to segregate along matrix grain boundaries, which could cause severe embrittlement. Herein, we utilized a plenary ball milling process to gradually introduce oxygen into pure Ti, which was found to be capable of doping up to 0.63 wt% of equivalent interstitial oxygen ([O]_eq = [O] + 2[N], in wt%) into the Ti matrix homogeneously. Tensile tests revealed that the Ti[sbnd]O with 0.63 wt% of [O]_eq exhibited an excellent ductility of 24.2 % in elongation and high tensile strength of 1018 MPa, which results in a high strengthening efficiency of 624 MPa per wt% of [O]_eq. A quantitative analysis on strengthening mechanism further confirmed the superior strengthening effect of interstitial oxygen via solid solution strengthening. This study may provide guidance for the development of high-performance yet cost-effective Ti materials.