Kinetics of dehydrogenation in Ti600, TC21 and Ti40 alloys

The dehydrogenation kinetics of Ti600, TC21 and Ti40 alloys has been studied using a tubular thermohydrogen processing furnace and simultaneous DTA-TG apparatus. The results show that the initial dehydrogenation temperatures in Ti600, TC21 and Ti40 alloys were 580 °C, 600 °C and 540 °C, respectively. At the initial stage of dehydrogenation, the passive layer on the alloy surface was the barrier to enhance the diffusion activation energy. Therefore, activation energy decreased with the increase of reacted fraction. At the initial stage, values of activation energy for the three alloys were 255 kJ/mol, 322 kJ/mol and 177 kJ/mol, respectively. After incubation period, the dehydrogenation average values of activation energy were 200 ± 5 kJ/mol, 240 ± 5 kJ/mol and 155 ± 5 kJ/mol, respectively.