Mechanical Properties of Oxide Dispersion Strengthened Pure Titanium Produced by Powder Metallurgy Method

摘要

Pure titanium has good specific properties i.e. low density of 4.5g/cm~3, extremely high resistance for corrosion and good elongation. However, its mechanical properties are not enough to be employed as structural parts and components. Accordingly, titanium alloys are often applied to industrial fields due to their high specific strength. However, the application is limited to high-performance products because of their expensive material cost and poor plastic formability at low temperature. In the present study, from a view point of cost reduction, pure titanium was used as a starting material. The materials design by oxide dispersion strengthening (ODS) was basically applied to improve the poor mechanical strength of pure titanium. TiO_2 powders were used as reinforcement dispersoids because of their easily obtainable and low material cost. Powder metallurgy (P/M) method was applied to fabricate TiO_2 particles reinforced pure titanium composite. Pure titanium powder and TiO_2 particles were elementally mixed by conventional mixing process. Their elemental mixture powders were consolidated by using spark plasma sintering (SPS) equipment to serve a high density compact billet. Subsequently, hot extrusion process was applied to the billet to prepare a full density rod specimen. The evaluation of mechanical properties at room temperature showed high tensile strength of 1040 MPa and good elongation of 25 % when the composite included 1.5mass% TiO_2 particles.