A titanium-nitrogen alloy with ultrahigh strength by ball milling and spark plasma sintering

The high strength and low cost of titanium alloys have led to the development of these alloys for aerospace applications. In this study, ultra-high-strength Ti–N alloys were fabricated by ball-milling (BM) and spark plasma sintering (SPS), and the effects of the nitrogen content on the microstructure and mechanical properties of the alloys were studied. TiN powder was used as the raw material for doping the alloys with N atoms, and the N content was controlled by tuning the amount of TiN powder added. The yield strength of the Ti–N alloys increased with an increase in the N content and surpassed 2000 MPa when the N content reached 2.66 wt%. Quantitative analysis using the Hall-Petch equation and Labusch model demonstrated that fine-grain strengthening and solution strengthening worked in synergy to enhance the strength of the Ti–N alloys. The ultra-high-strength Ti–N alloys can be applied in the aerospace field for structure use, such as aircraft engines, fasteners, and burn-resistant materials. The preparation of novel Ti–N alloys validates the theoretical application of ubiquitous elements in titanium alloys.