Kinetics of order-disorder transformations in the heusler AuAgZn2 alloy

Abstract The kinetics of order-disorder transformations in the Heusler AuAgZn 2 alloy was analyzed theoretically by taking into account the interchanges of atoms with neighboring vacancies. The variation of the degrees of the B2- and the L2 1 -type orders, S 1 and S H respectively, was calculated during isothermal annealing and during heating or cooling processes. During isothermal annealing, S 1 , and S H showed the relaxation phenomena. During heating and cooling processes, S l , S H − T curves showed hysteresis. Moreover, during heating, the S 1 − T curve had a minimum at the critical temperature of the L2 1 -type structure T c 2 , which was dependent on the heating rate of specimen. The interchanges of atoms with vacancies between the 1st nearest neighbors as well as those between the 2nd nearest neighbors were found to play an important role on the kinetic behavior of ordering in the Heusler alloy.