A continuum model accounting for the effect of the initial and evolving microstructure on the evolution of dynamic recrystallization

Harmen Kooiker*, Emin S. Perdahcioglu, Ton Van Den Boogaard

*Corresponding author for this work

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    Abstract

    Laser assisted forming is a process which is increasingly being adopted by the industry. Application of heat by a laser to austenitic stainless steel (ASS) sheet provides local control over formability and strength of the material. The hot forming behavior of ASS is characterized by significant dynamic recovery and dynamic recrystallization. These two processes lead to a softening stress-strain response and have a significant impact on the microstructure of the material. Most of the research performed on hot forming of ASS focuses on dynamic recrystallization and then specifically on the behavior of the annealed state, consisting of relatively large equiaxed austenite grains. However, in industry it is common to use cold rolled ASS sheet which is a mixture of austenite and martensite. Application of a laser heat treatment to the cold rolled grades of ASS induces a so-called ‘reverse’ transformation of martensite to austenite which, depending on the exact time-temperature combinations, leads to an austenite grain size in the range of nano-to micrometer. It is known from experiments that the effect of initial grain size on dynamic recrystallization is significant, especially on the initial stages of recrystallization. Therefore any continuum model capable of describing hot forming of cold rolled ASS should include the effect of the initial grain size. In this work a physically based continuum model for dynamic recrystallization is presented which accounts for the effect of the initial and evolving grain size on the evolution of dynamic recrystallization. It is shown that the initial grain size can be accounted for by incorporating its effect on the availability of preferred nucleation sites, i.e. grain edges. The new model is compared to experimental results and it is shown that the model correctly predicts accelerated recrystallization with decrease in grain size and that there is a weak dependence of the dynamically recrystallized grain size on the initial grain size. Furthermore predicted recrystallized grain sizes are in good agreement with the experimentally measured values.

    Original languageEnglish
    Title of host publicationXIV International Conference on Computational Plasticity, Fundamentals and Applications, COMPLAS 2017
    EditorsE. Onate, D.R.J. Owen, D. Peric, M. Chiumenti
    PublisherInternational Center for Numerical Methods in Engineering
    Pages308-318
    Number of pages11
    Volume2017-January
    ISBN (Electronic)9788494690969
    Publication statusPublished - 2017
    EventXIV International Conference on Computational Plasticity - Fundamentals and Applications 2017: Fundamentals and Applications - Barcelona, Spain
    Duration: 5 Sep 20177 Sep 2017
    Conference number: 14
    http://congress.cimne.com/complas2017/frontal/Series.asp

    Conference

    ConferenceXIV International Conference on Computational Plasticity - Fundamentals and Applications 2017
    Abbreviated titleCOMPLAS 2017
    CountrySpain
    CityBarcelona
    Period5/09/177/09/17
    Internet address

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    Keywords

    • Constitutive modeling
    • Dynamic recrystallization
    • Grain size
    • Microstructure

    Cite this

    Kooiker, H., Perdahcioglu, E. S., & Van Den Boogaard, T. (2017). A continuum model accounting for the effect of the initial and evolving microstructure on the evolution of dynamic recrystallization. In E. Onate, D. R. J. Owen, D. Peric, & M. Chiumenti (Eds.), XIV International Conference on Computational Plasticity, Fundamentals and Applications, COMPLAS 2017 (Vol. 2017-January, pp. 308-318). International Center for Numerical Methods in Engineering.