Predicting plastic flow and irradiation hardening of iron single crystal with mechanism-based continuum dislocation dynamics
Li D, HM Zbib, X Sun, and MA Khaleel. 2014. "Predicting plastic flow and irradiation hardening of iron single crystal with mechanism-based continuum dislocation dynamics." International Journal of Plasticity 52(1):3-17. doi:10.1016/j.ijplas.2013.01.015
Continuum Dislocation Dynamics (CDD) with a novel constitutive law based on dislocation density evolution mechanism with properties retrievable from discrete dislocation dynamics was proposed to investigate the deformation behavior of single crystals. Dislocation density evolution law in this model is mechanism based with parameters measured from experiments or simulated from lower length scale models, not an empirical law with parameters back fitting from the flow curves. Applied in single crystal irons, this model was validated by experimental data and compared with traditional single crystal constitutive model with Hutchinson type hardening law and dislocation based hardening law. CDD model demonstrated higher fidelity than other constitutive models when anisotropic single crystal deformation behaviors were investigated. Due to the mechanism of constitutive models, the traditional Hutchinson type hardening laws and other constitutive laws based on a Kock formulated dislocation density evolution law will only succeed in a limited number of loading directions. The main advantage of CDD is the original science-based dislocation density evolution law to describe the mesoscale structure evolution. Another advantage of CDD is cross slip incorporated, which is very important under the loading condition with only one primary slip system activated. Besides the dislocation hardening, CDD also takes into consideration of dislocation defect interaction. Irradiation hardening of single crystal irons was simulated in this study with validation from experimental results. The toolsets developed from CDD will benefit to Integrated Computational Materials Engineering (ICME).