An investigation of the deformation mechanism in grain size-sensitive Newtonian creep

Journal Article · Wed Apr 19 04:00:00 EDT 2000 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(99)00450-4· OSTI ID:20034186

Wang, J N

Creep of polycrystalline materials at low stresses often shows a linear relationship between strain rate and stress, and an inverse dependence on grain size squared or cubed. Attribution of this behavior to diffusional creep or grain boundary sliding (GBS) has evoked much confusion and controversy in the literature. A model is proposed to unify these two creep mechanisms. The model predicts a change in dominant mechanism from diffusional creep to GBS accommodated mainly by diffusion or by GBS itself as the amount of matter moved by diffusion decreases. Corresponding to this change, the model also predicts a spectrum of creep rate with the absolute value being dependent upon the extent of diffusion accommodation. Although experimental data exhibit scattering, most of them are in very good agreement with the prediction of the GBS model. Therefore, it is suggested that the Newtonian creep behavior with grain size dependence be induced by GBS rather than by conventional diffusion creep as believed before.

• Research Organization: Shanghai Jiao Tong Univ. (CN)
• OSTI ID: 20034186
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 7 Vol. 48; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CREEP
DIFFUSION
GRAIN BOUNDARIES
GRAIN SIZE
MATHEMATICAL MODELS
POLYCRYSTALS
STRAIN RATE
STRESSES