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A dislocation-based model for high temperature cyclic viscoplasticity of 9-12Cr steels

Barrett, Richard A.
; 
O'Donoghue, Peter E.
; 
Leen, Sean B.
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Identifiers
http://hdl.handle.net/10379/5459
 https://doi.org/10.13025/19160
Publication Date
2015-06-22
Keywords
P91 steel, Dislocation density, Precipitate hardening, Cyclic softening, Cyclic viscoplasticity
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Article
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Citation
Barrett, RA, O Donoghue, PE, Leen, SB (2015) 'A dislocation-based model for high temperature cyclic viscoplasticity of 9-12Cr steels'. Journal Of Pressure Vessel Technology, .
Abstract
A dislocation-based model for high temperature cyclic viscoplasticity in 9–12Cr steels is presented. This model incorporates (i) cyclic softening via decrease in overall dislocation density, loss of low angle boundary dislocations and coarsening of the microstructure and (ii) kinematic hardening via precipitate strengthening and dislocation substructure hardening. The effects of the primary micro-structural variables, viz. precipitate radii, dislocation density and martensitic lath width on cyclic viscoplasticity, reveal a size effect of initial precipitate radii and volume fraction, with smaller radii and a higher density of precipitate producing a stronger material. A similar effect is also predicted for initial martensitic lath width at temperatures below 500 °C. The model is intended for microstructure sensitive design of high temperature materials and components for next generation power plant technology.
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Publisher
Elsevier ScienceDirect
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Attribution-NonCommercial-NoDerivs 3.0 Ireland
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Mechanical Engineering (Scholarly Articles)