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Effect of Crystal Orientation on the Mechanical Behavior of Magnesium Oxide at High Temperatures
Author(s) -
DAY R. B.,
STOKES R. J.
Publication year - 1966
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.1151-2916.1966.tb13211.x
Subject(s) - materials science , slip (aerodynamics) , necking , slipping , substructure , ultimate tensile strength , crystal twinning , dislocation , oblique case , composite material , crystallography , brittleness , single crystal , geometry , structural engineering , chemistry , microstructure , thermodynamics , physics , linguistics , mathematics , philosophy , engineering
The high‐temperature deformation of magnesia single crystals with a [110] tensile axis is described and related to previous observations on [001] crystals. The [110] tensile axis favors slip on systems with oblique vectors (i.e. at 120°). Two main modes of deformation are identified and distinguished by the interpenetrability of oblique slip: (1) Between 1400° and 1700°C interpenetration does not occur. The crystal becomes subdivided into distinct blocks slipping on different systems. These blocks are separated by sharp kink boundaries which act as barriers to further slip. Voids form in the kink interfaces and lead to brittle fracture. (2) Above 1700°C slip on all systems interpenetrates and a stable substructure develops throughout the gage section. At high strains the single crystal recrystallizes. The specimen work hardens and elongates 100% before necking down to completely ductile fracture. This behavior is discussed in terms of dislocation interactions.