Mechanism-based modeling of solute strengthening: Application to thermal creep in Zr alloy

Wen, Wei; Capolungo, Laurent; Tome, Carlos N.

doi:10.1016/j.ijplas.2018.03.003

Title: Mechanism-based modeling of solute strengthening: Application to thermal creep in Zr alloy

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Abstract

In this paper, a crystallographic thermal creep model is proposed for Zr alloys that accounts for the hardening contribution of solutes via their time-dependent pinning effect on dislocations. The core-diffusion model proposed by Soare and Curtin (2008a) is coupled with a recently proposed constitutive modeling framework (Wang et al., 2017, 2016) accounting for the heterogeneous distribution of internal stresses within grains. The Coble creep mechanism is also included. This model is, in turn, embedded in the effective medium crystallographic VPSC framework and used to predict creep strain evolution of polycrystals under different temperature and stress conditions. The simulation results reproduce the experimental creep data for Zircaloy-4 and the transition between the low (n~1), intermediate (n~4) and high (n~9) power law creep regimes. This is achieved through the dependence on local aging time of the solute-dislocation binding energy. The anomalies in strain rate sensitivity (SRS) are discussed in terms of core-diffusion effects on dislocation junction strength. The mechanism-based model captures the primary and secondary creep regimes results reported by Kombaiah and Murty (2015a, 2015b) for a comprehensive set of testing conditions covering the 500–600 °C interval, stresses spanning 14–156 MPa, and steady state creep rates varying between 1.5·10^-9s^-1 to 2·10^-3s^-1. Theremore »« less

Authors:

Wen, Wei ^[1]; Capolungo, Laurent ^[1]; Tome, Carlos N. ^[1]

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:: 2018-03-11

Research Org.:: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:: USDOE Office of Nuclear Energy (NE)

OSTI Identifier:: 1430009

Alternate Identifier(s):: OSTI ID: 1496331

Report Number(s):: LA-UR-17-28518
Journal ID: ISSN 0749-6419

Grant/Contract Number:: AC52-06NA25396; AC05-00OR22725

Resource Type:: Accepted Manuscript

Journal Name:: International Journal of Plasticity

Additional Journal Information:: Journal Volume: 106; Journal ID: ISSN 0749-6419

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE

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                    Wen, Wei, Capolungo, Laurent, and Tome, Carlos N. Mechanism-based modeling of solute strengthening: Application to thermal creep in Zr alloy.  United States: N. p., 2018. 
Web.  doi:10.1016/j.ijplas.2018.03.003.

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                    Wen, Wei, Capolungo, Laurent, & Tome, Carlos N. Mechanism-based modeling of solute strengthening: Application to thermal creep in Zr alloy.  United States.  https://doi.org/10.1016/j.ijplas.2018.03.003

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                    Wen, Wei, Capolungo, Laurent, and Tome, Carlos N. Sun .  
"Mechanism-based modeling of solute strengthening: Application to thermal creep in Zr alloy".  United States.  https://doi.org/10.1016/j.ijplas.2018.03.003.  https://www.osti.gov/servlets/purl/1430009.

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@article{osti_1430009,

  title        = {Mechanism-based modeling of solute strengthening: Application to thermal creep in Zr alloy},

  author       = {Wen, Wei and Capolungo, Laurent and Tome, Carlos N.},

  abstractNote = {In this paper, a crystallographic thermal creep model is proposed for Zr alloys that accounts for the hardening contribution of solutes via their time-dependent pinning effect on dislocations. The core-diffusion model proposed by Soare and Curtin (2008a) is coupled with a recently proposed constitutive modeling framework (Wang et al., 2017, 2016) accounting for the heterogeneous distribution of internal stresses within grains. The Coble creep mechanism is also included. This model is, in turn, embedded in the effective medium crystallographic VPSC framework and used to predict creep strain evolution of polycrystals under different temperature and stress conditions. The simulation results reproduce the experimental creep data for Zircaloy-4 and the transition between the low (n~1), intermediate (n~4) and high (n~9) power law creep regimes. This is achieved through the dependence on local aging time of the solute-dislocation binding energy. The anomalies in strain rate sensitivity (SRS) are discussed in terms of core-diffusion effects on dislocation junction strength. The mechanism-based model captures the primary and secondary creep regimes results reported by Kombaiah and Murty (2015a, 2015b) for a comprehensive set of testing conditions covering the 500–600 °C interval, stresses spanning 14–156 MPa, and steady state creep rates varying between 1.5·10-9s-1 to 2·10-3s-1. There are two major advantages to this model with respect to more empirical ones used as constitutive laws for describing thermal creep of cladding: 1) specific dependences on the nature of solutes and their concentrations are explicitly accounted for; 2) accident conditions in reactors, such as RIA and LOCA, usually take place in short times, and deformation takes place in the primary, not the steady-state creep stage. Finally, as a consequence, a model that accounts for the evolution with time of microstructure is more reliable for this kind of simulation.},

  doi          = {10.1016/j.ijplas.2018.03.003},

  journal      = {International Journal of Plasticity},

  number       = ,

  volume       = 106,

  place        = {United States},

  year         = {2018},

  month        = {3}

}

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