2009 Volume 50 Issue 12 Pages 2751-2756
Titanium (Ti) alloys are possible to be applied to various products such as aircraft, automotive and motor cycles industries because of their weight reduction effect, superior mechanical responses and high corrosion resistance. Ti-6Al-4V (Ti64) is one of the most common Ti alloys used in structural components. It shows high tensile strength of 900 MPa or more. On the other hand, its applications are limited to high-performance products because of both its poor plastic formability and high cost due to the addition of vanadium element and difficult melting process.
In this study, the highly strengthened pure titanium has been developed using cheap sponge Ti powders via repeated plastic deformation, avoiding the melting process. The main strengthening mechanism of this material is the oxide dispersion strengthening (ODS) by the in-situ formed TiO2 fine dispersoids during the repetitive plastic deformation of sponge Ti powders. Roll-Compaction (RCP) process, consisting of cold powder rolling and fragmentation, was employed to induce much plastic strain into the matrix of the Ti powders. Subsequently, the grain refinement was also obtained to enhance the mechanical properties. The extruded sponge Ti powder composites reinforced with TiO2 particles indicated high tensile strength of 640 MPa and enough elongation of 17.2% after RCP process with 20 cycles.