Microstructure evolution of stainless steel subjected to biaxial load path changes: In-situ neutron diffraction and multi-scale modeling

https://doi.org/10.1016/j.ijplas.2019.06.006Get rights and content
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Highlights

  • Lattice strain and intensity evolutions analysed for 45° and 90° load path changes.

  • For the first time, simulations well predict both lattice strain and intensity changes.

  • Role of elastic anisotropy, plastic slip and grain neighborhood is studied in detail.

  • Simulations show that grain neighborhood significantly affects intensity variations.

  • Grains contributing to {311} reflection change although total intensity stays constant.

Abstract

The lattice strain and intensity evolution obtained from in-situ neutron diffraction experiments of 316L cruciform samples subjected to 45° and 90° load path changes are presented and predicted using the multi-scale modeling approach proposed in Upadhyay et al., IJP 108 (2018) 144-168. At the macroscale, the multi-scale approach uses the implementation of the viscoplastic self-consistent polycrystalline model as a user-material into ABAQUS finite element framework to predict the non-linearly coupled gauge stresses of the cruciform geometry. The predicted gauge stresses are then used to drive the elasto-viscoplastic fast Fourier transform polycrystalline model to predict the lattice strain and intensity evolutions. Both models use the same dislocation density based hardening law suitable for load path changes. The predicted lattice strain and intensity evolutions match well with the experimental measurements for all reflections studied. The simulation results are analyzed in detail to understand the role of elastic anisotropy, plastic slip, grain neighborhood interactions and cruciform geometry on the microstructural evolution during biaxial load path changes.

Keywords

Strain path change
A dislocations
B polycrystalline material
B crystal plasticity
C finite elements

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1

Current address: LMS, C.N.R.S., Ecole Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France. email: [email protected].