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Plastic Deformation of MgO Single Crystals up to 1600°C
Author(s) -
Copley Stephen M.,
PASK JOSEPH A.
Publication year - 1965
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1965.tb16050.x
Subject(s) - materials science , dislocation , stress (linguistics) , hardening (computing) , composite material , strain hardening exponent , strain rate , deformation (meteorology) , single crystal , yield (engineering) , plasticity , strain (injury) , crystallography , chemistry , philosophy , linguistics , layer (electronics) , medicine
Stress‐strain curves are presented for MgO single crystals, compressed with (100) and (111) stress axes, for temperatures from 1000° to 1600°C. The yield stress of (100) specimens decreases slightly in this temperature range. The strain‐hardening rate passes through a maximum at about 1100°C and decreases by a factor of about 8 at 1600°C. Above about 1100°C, the strain rate of (100) specimens is considerably less sensitive to changes in stress and the shape of the stress‐strain curves changes. The yield stress of (111) specimens decreases rapidly with increasing temperature without a change of slope up to 1600°C. The ratio of the yield stresses for (111) and (100) specimens decreases continually from 1200° to 1600°C. Various stress rates were used to obtain a measure of strain hardening at 1300°C. Static recovery experiments were carried out at 1000° and 1400°C. At 1000°C static pinning occurred during the unloaded period; at 1400°C orthorecovery occurred. Stress‐strain curves were analyzed by a dynamic approach based on the length of moving dislocation line in the crystal and the average dislocation velocity.