Abstract
The kinetic equations of B2 and DO3 types of ordering in binary alloys were derived by taking into account the mechanism of atomic migration through vacancies within the Bragg-Williams approximation. The kinetic data of ordering in Fe3Al alloys obtained by X-ray diffraction and measurement of electrical resistivity were treated with the kinetic equations. The variation in the degrees of order obtained by X-ray diffraction with cooling the alloy at various rates is reproduced satisfactorily by solving the equations numerically. The resistivity changes during isothermal annealing after quenching from various temperatures are analysed with the equations to determine the vacancy formation energy, It is expected from the kinetic equations that the B2 type of ordering takes place too rapidly to be prevented by cooling at the rate smaller than 107°C/sec, but that the DO3 type of ordering takes place slowly enough to be prevented by cooling at the rate of 103°C/sec.
