Impurity effects and reaction kinetics of the pressure-induced α → ω transformation in Ti

The effects of impurities on the transformation pressure and the reaction kinetics of α → ω transformation in Ti metal were studied by the electrical resistivity technique upto a pressure of 80 kbar. The ω-start pressure is found to be lowered when the soaking time was varied from 3 to 10 min. Under identical (viz. 10 min) soaking conditions, the ω-start pressure varied from 29 to 60 kbar, following the increase in oxygen content and other impurity levels in the samples. After the onset of ω, the increase in electrical resistance with time under isothermal-isobaric conditions is typical of that of an isothermal martensite.