On basal slip and basal twinning in sapphire ({alpha}-Al{sub 2}O{sub 3}). 1: Basal slip revisited

Journal Article · Wed May 01 04:00:00 EDT 1996 · Acta Materialia

DOI:https://doi.org/10.1016/1359-6454(95)00264-2· OSTI ID:247965

Bilde-Soerensen, J B; Lawlor, B F; Geipel, T; Pirouz, P; Heuer, A H; Lagerloef, K P.D. ^[1]

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1. Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Materials Science and Engineering

The motion of partial dislocations in sapphire ({alpha}-Al{sub 2}O{sub 3}) is analyzed. Crystallographic arguments suggest that the basal slip plane should be a plane passing through the normally-vacant octahedral sites defined by the anion sublattice. This definition of the basal slip plane implies that half of the cations lying between two adjacent anion layers are above and the other half are below the slip plane. The stacking faults that would be created by the motion of a dissociated basal dislocation differs in structure and energy, depending on whether the partial is leading or trailing. Thus, the motion of a partial in its favorable (lower energy) direction creates a stacking fault with a stacking /sequence in which the cations are in a localized twin symmetry, whereas the motion of a partial in its unfavorable (higher energy) direction is ``forbidden``.

• DOE Contract Number: FG02-93ER45496
• OSTI ID: 247965
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 5 Vol. 44; ISSN XZ504Y; ISSN 1359-6454
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
BRITTLE-DUCTILE TRANSITIONS
CRYSTALLOGRAPHY
DEFORMATION
DISLOCATIONS
PLASTICITY
SAPPHIRE
SLIP
SLIP VELOCITY
STACKING FAULTS
TEMPERATURE DEPENDENCE