Strengthening behaviour and mechanisms of extruded powder metallurgy pure Ti materials reinforced with ubiquitous light elements

Abstract

Ubiquitous light elements (ULEs) like oxygen (O), nitrogen (N), carbon (C) and hydrogen (H) can be the key additive elements to achieve the high specific strength and cost-effectiveness of powder metallurgy (PM) titanium (Ti) materials. They have high potential to be employed as promising useful reinforcements of conventional expensive alloying elements like vanadium (V) and Niobium (Nb). In this study, two ULEs, oxygen and hydrogen, were induced into pure Ti matrix via the PM route, and then the processed Ti powders were consolidated into the extruded Ti–O–H materials. The additive ULEs’ contribution to the microstructures and strengthening behaviour of Ti wrought materials was investigated in detail. The extruded Ti–0.97O–0.11H specimen exhibited an excellent combination of ultimate tensile strength (UTS) of 1158 MPa and tensile elongation of 23.9%, which were superior to those of Ti–6Al–4V alloy (UTS: 1047 MPa, elongation: 16.6%).

Keywords:

• Titanium
• Oxygen
• Hydrogen
• Solid solution hardening
• Hot extrusion
• Powder metallurgy

Acknowledgements

This work was partially supported by JSPS Grant-in-Aid for Scientific Research (A) 25249102, and Environment Research and Technology Development Fund 3K133002 of the Ministry of the Environment, Japan.