Journal article
Lattice continuum and diffusional creep
Proceedings of the Royal Society. A, Mathematical, physical, and engineering sciences, Vol.472(2188), pp.20160039-20160039
04/2016
Handle:
https://hdl.handle.net/2376/118115
PMCID: PMC4892284
PMID: 27274696
Abstract
Diffusional creep is characterized by growth/disappearance of lattice planes at the crystal boundaries that serve as sources/sinks of vacancies, and by diffusion of vacancies. The lattice continuum theory developed here represents a natural and intuitive framework for the analysis of diffusion in crystals and lattice growth/loss at the boundaries. The formulation includes the definition of the Lagrangian reference configuration for the newly created lattice, the transport theorem and the definition of the creep rate tensor for a polycrystal as a piecewise uniform, discontinuous field. The values associated with each crystalline grain are related to the normal diffusional flux at grain boundaries. The governing equations for Nabarro-Herring creep are derived with coupled diffusion and elasticity with compositional eigenstrain. Both, bulk diffusional dissipation and boundary dissipation accompanying vacancy nucleation and absorption, are considered, but the latter is found to be negligible. For periodic arrangements of grains, diffusion formally decouples from elasticity but at the cost of a complicated boundary condition. The equilibrium of deviatorically stressed polycrystals is impossible without inclusion of interface energies. The secondary creep rate estimates correspond to the standard Nabarro-Herring model, and the volumetric creep is small. The initial (primary) creep rate is estimated to be much larger than the secondary creep rate.
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Details
- Title
- Lattice continuum and diffusional creep
- Creators
- Sinisa Dj Mesarovic - School of Mechanical and Materials Engineering, Washington State University , Pullman, WA 99164, USA
- Publication Details
- Proceedings of the Royal Society. A, Mathematical, physical, and engineering sciences, Vol.472(2188), pp.20160039-20160039
- Academic Unit
- Mechanical and Materials Engineering, School of
- Publisher
- England
- Identifiers
- 99900548168101842
- Language
- English
- Resource Type
- Journal article