Equilibrium concentration of vacancies and divacancies in binary ordering alloys with fcc-lattice

摘要

A calculation is made of equilibrium concentration of vacancies and divacancies in a binary ordering alloy with an fcc-lattice. It is shown that due to low concentration of both types of defects their formation occurs independently of each other. Unlike that of vacancies, the formation of divacancies in an ordered state is not affected by the changes in entropy caused by ordering. Due to this, we may introduce the bonding energy of divacancies in the alloys for a disordered state only, where it appears as a linear-quadratic function of composition.