A multi-scale model of dislocation plasticity in α-Fe: Incorporating temperature, strain rate and non-Schmid effects

Journal Article · Mon Jan 05 00:00:00 EST 2015 · International Journal of Plasticity

DOI:https://doi.org/10.1016/j.ijplas.2014.12.005· OSTI ID:1258482

Lim, H. ^[1]; Hale, L. M. ^[2]; Zimmerman, J. A. ^[3]; Battaile, C. C. ^[1]; Weinberger, C. R. ^[4]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2. National Institute of Standards and Technology, Gaithersburg, MD (United States)
3. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
4. Drexel Univ., Philadelphia, PA (United States)

In this study, we develop an atomistically informed crystal plasticity finite element (CP-FE) model for body-centered-cubic (BCC) α-Fe that incorporates non-Schmid stress dependent slip with temperature and strain rate effects. Based on recent insights obtained from atomistic simulations, we propose a new constitutive model that combines a generalized non-Schmid yield law with aspects from a line tension (LT) model for describing activation enthalpy required for the motion of dislocation kinks. Atomistic calculations are conducted to quantify the non-Schmid effects while both experimental data and atomistic simulations are used to assess the temperature and strain rate effects. The parameterized constitutive equation is implemented into a BCC CP-FE model to simulate plastic deformation of single and polycrystalline Fe which is compared with experimental data from the literature. This direct comparison demonstrates that the atomistically informed model accurately captures the effects of crystal orientation, temperature and strain rate on the flow behavior of siangle crystal Fe. Furthermore, our proposed CP-FE model exhibits temperature and strain rate dependent flow and yield surfaces in polycrystalline Fe that deviate from conventional CP-FE models based on Schmid's law.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1258482
• Alternate ID(s): OSTI ID: 1422664
• Report Number(s): SAND-2014-15610J; PII: S0749641914002356
• Journal Information: International Journal of Plasticity, Vol. 73, Issue C; ISSN 0749-6419
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Fe
non-Schmid
temperature
strain rate
molecular dynamics
crystal plasticity