Thermodynamic Properties of Dilute Titanium-Oxygen Solid Solution in Beta Phase

Abstract

Titanium-oxygen alloys were equilibrated with calcium and calcium oxide at temperatures between 1173 and 1373 K. Equilibrium oxygen concentrations, in the order of 490 mass ppm at 1273 K, were obtained. From the analyzed oxygen concentrations in titanium, thermodynamic properties of oxygen in β-titanium-oxygen alloys were evaluated by using the standard free energy of formation of CaO. A relationship involving oxygen potential, temperature and concentration of oxygen in the β-titanium was determined as follows;
1/2 ln (P_O2/101325 Pa)= ln (mass%O)+10.6−70100/T [1173-1373 K]