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On the thermodynamic theory of dislocation etch‐pit formation
Author(s) -
Koziejowska A.,
Sangwal K.
Publication year - 1985
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170200405
Subject(s) - dislocation , nucleation , radius , activation energy , thermodynamics , chemistry , logarithm , crystallography , physics , mathematics , mathematical analysis , computer security , computer science
A logarithmic function of total dislocation energy, which includes Cabrera's and Schaarwächter's dislocation energy equations, is used to derive thermodynamic conditions for etch‐pit formation at dislocation sites. It is found that Cabrera's mechanism holds when the ratio of dislocation core radius r h to Frank's radius r F approaches zero. When 0 < r h / r F < 1, Cabrera‐type mechanism also holds, but the activation energy barrier is smaller than that in the original Cabrera's model and the undersaturation barrier Δμ* for spontaneous nucleation increases with an increase in r h / r F ratio. When r h / r F =1, the value of Δμ* is four‐times the value predicted by Cabrera's model. For r h / r F > 1, Schaarwächtertype mechanism involving no undersaturation barrier holds. A resume of Cabrera's and Schaarwächter's theories is also given.