Model for creep based on the climb of dislocations at grain boundaries

Journal Article · Thu Feb 01 04:00:00 EST 1979 · Acta Metall.; (United States)

DOI:https://doi.org/10.1016/0001-6160(79)90093-2· OSTI ID:6361672

Spingarn, J R; Nix, W D

A model for creep based on the climb of dislocations at grain boundaries is presented. It is shown that when a sliding interface or slip band intersects a grain boundary, a traction distribution is established on the boundary. The diffusional flow induced by these tractions results in a steady state creep process. This slip band model predicts an activation energy corresponding to grain boundary self diffusion, with a stress exponent and a grain size dependence which increase and decrease, respectively, as the applied stress increases. The theoretically determined creep rates are in good agreement with the data for metals and alloys which deform by grain boundary sliding and exhibit superplastic flow properties. Other models for creep controlled by grain boundary diffusion are briefly reviewed and compared with the present model. It is concluded that superplastic deformation involves both purely diffusional flow and dislocation motion.

• Research Organization: Stanford Univ., CA
• OSTI ID: 6361672
• Journal Information: Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 27:2; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ACTIVATION ENERGY
ALLOYS
CARBON ADDITIONS
CREEP
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISLOCATIONS
ELEMENTS
ENERGY
GRAIN BOUNDARIES
GRAIN SIZE
IRON ALLOYS
IRON BASE ALLOYS
LINE DEFECTS
MECHANICAL PROPERTIES
METALS
MICROSTRUCTURE
NICKEL
SIZE
SLIP
STRAIN RATE
TIN
TIN ALLOYS
TRANSITION ELEMENTS
ZINC
ZINC ALLOYS