Pure titanium with high strength and excellent ductility by solid solute oxygen strengthening via powder metallurgy route

摘要

Rare metals-free pure titanium material with a good balance of high strength and excellent ductility was produced by oxygen solid solution via powder metallurgy (P/M) process. Oxygen atoms are originated from TiO_2 particles or O_2 gas contained in atmosphere. When 1.5-2.5 at.% oxygen contained in P/M pure titanium materials, they showed remarkably high tensile yield stress (YS) of 820-860 MPa and suitable elongation of 24-26% at ambient temperature. These performances were superior to the traditionally commercialized titanium alloys such as wrought Ti-6%A1-4%V alloy. XRD analysis suggested a large lattice expansion along c axis of hcp-Ti due to the above solid solution of oxygen atoms. Labusch model for estimation of YS increment by light elements solid solution strengthening mechanism was employed in this study. The calculation results revealed a good agreement with the experimental data in tensile test.