Investigation of the heat of polymorphous transformation in zirconium by the method of pulsed electric heating

Results are given of the determination of the heat of polymorphous transformation in zirconium during resistive electric heating of specimens at rates from $10^3$ to $10^4$ K/s. A comparative analysis of the time dependences of temperature and resistance is used to demonstrate that the beginning and completion of phase rearrangement occur nonsimultaneously over the entire working length of the specimen. A procedure is suggested for obtaining refined data on the thermal effect, based on the calculation of the fraction of the working section, which has completely passed over to a new phase during a time interval identified by the heating thermogram. The mean value of the heat of $\alpha$–$\beta$ phase transition obtained by this procedure is $55.4$ J/g. The obtained data are compared with those available in the literature.