Advanced mechanical properties of powder metallurgy commercially pure titanium with a high oxygen concentration

Oxygen is known to have a significant impact on the strength of Ti alloys, whereas it can also reduce the ductility substantially. Thus, the usage of oxygen to strengthen Ti is restricted in the industry. In this study, we rekindled the research of oxygen behavior in Ti with the purpose of developing Ti alloys with high strength and suitable ductility by using no expensive and poisonous element. To this end, experiments of producing high performance commercially pure Ti using only oxygen solid solution were carried out. The oxygen element was introduced into the Ti by two different powder metallurgy methods. The microstructural examination and mechanical test were performed for the samples, which indicated a strong hardening effect of oxygen in spite of the processing routes. Most importantly, the results suggested that a high elongation to failure of over 20% can still be obtained in the samples having yield stress over 800 MPa, up to an oxygen content of 0.8 wt%, which is far beyond the previously recognized limit.