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Unstable Dislocations in Anisotropic Crystals
Author(s) -
Head A. K.
Publication year - 1967
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.19670190121
Subject(s) - brass , anisotropy , dislocation , condensed matter physics , instability , materials science , niobium , crystallography , crystal (programming language) , physics , metallurgy , chemistry , mechanics , copper , optics , computer science , programming language
In an elastically anisotropic crystal, the energy of a dislocation depends on the crystallographic direction of the dislocation line. A straight dislocation which is in a high energy direction may be unstable with its energy decreasing if it changes to a zig‐zag shape. The relation between two different criteria of instability is clarified. The theory is used to examine seven possible slip systems in three metals. Instabilities are predicted for six systems in β‐brass, two in iron, and none in niobium. Tables are given of the predicted instabilities for the 〈110〉 {111} f.c.c. system and the 〈111〉 {110} b.c.c. system for a range of elastic constants. A preliminary report is given of the observation of this phenomenon in β‐brass.