Open AccessORDERING AND VACANCY DIFFUSION IN AuCu<sub>3</sub>
Author(s) -
Sze Shih-Yuan
Publication year - 1957
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.13.245
Subject(s) - vacancy defect , copper , boltzmann constant , thermodynamics , activation energy , materials science , atom (system on chip) , condensed matter physics , diffusion , fick's laws of diffusion , atomic physics , physics , chemistry , computer science , embedded system , metallurgy
It is shown that the probability of an disordered atom to be ordered in unit time can be correlated to the coefficient of diffusion by the relation a=9/4 d/a2 (m2/m1)1/2 (△S2-△S1)/k(Tc/T-1) where a=the probability of ordering, D=the coefficient of diffusion, a =the lattice constant of AuCu3,m1 and m2 the mass of an atom of gold and copper respectively,△S1, △S2 being respectively the entropy change when a gold and a copper atom jumps to a neighboring vacancy, k, the Boltzmann constant, Tc, T, the critical temperature and the absolute temperature under consideration.This relation has been verified with experimental data. With experimental value of a and D0, it gives an activation energy of 2.10 eV which is equal to the activation energy of self-diffusion of copper within the limits of experimental accuracy. This expression explains the existance of a temperature at which the rate of ordering is maximum both qualitatively and quantitatively.