The oxygen concentration in commercial Ti-6Al-4 V alloys was reduced to less than 400 ppm in this study by the method of solid state re-deoxidation, using calcium as a reductant. The concentration of oxygen in the deoxidised Ti-6Al-4 V alloy was 630 ppm at the optimum deoxidation temperature of 1000°C. When the degree of vacuum was increased and re-deoxidation was carried out, the oxygen concentration decreased to 355 ppm. Therefore, it is possible to prepare a Ti-6Al-4 V alloy with an oxygen concentration of less than 400 ppm by using the solid state re-deoxidation method at a high degree of vacuum of 1.5 × 10-6 Torr.
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