Deoxidation of Ti–Al intermetallics via hydrogen treatment

Alloys of Ti–47Al were deoxidized via a simple method called hydrogen treatment (HT), which involves deoxidation with hydrogen in a melting process. Because of the increase in the partial pressure of hydrogen and the melting duration, the oxygen content of the alloys greatly decreased after HT. Activated hydrogen atoms dissociated at high temperatures, and the hydrogen molecules in the melting chamber seemed to affect the deoxidation reactions, which are represented by the following equations: O + 2H = H2O and O + H2 = H2O. Based on a comparison of the changes in Gibbs free energy, the hydrogen atoms were found to play a major role in deoxidation.