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Creep Due to a Non‐Newtonian Grain Boundary Phase
Author(s) -
Chadwick Margaret M.,
Wilkinson David S.,
Dryden John R.
Publication year - 1992
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.1151-2916.1992.tb05582.x
Subject(s) - creep , materials science , newtonian fluid , grain boundary , composite material , tension (geology) , strain rate , phase (matter) , diffusion creep , compression (physics) , anisotropy , mechanics , flexural strength , steady state (chemistry) , thermodynamics , microstructure , chemistry , physics , optics , organic chemistry
A model has been developed for creep due to viscous flow in a material containing a non‐Newtonian, amorphous grain boundary phase. The model describes the process whereby glass is squeezed out from between grain boundary layers in compression, and flows toward grain boundary layers under tension. A pseudo steady state, in which the creep rate is constant, is seen at small strains. However, beyond a critical strain, the strain rate starts to decrease rapidly, and no creep is possible once adjacent grains come into contact. The maximum possible strain is twice as large in tension as in compression. This leads to a form of anisotropy which may explain the shift in neutral axis which occurs during flexural creep.