Highlights

• •Dislocation patterns of more than 1000 grains with defined loading conditions are observed by an integrated experimental approach combining DIC, EBSD and ECCI.

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• •Taylor factor is found to represent the crystallographic orientation information in polycrystalline materials more accurately than the commonly used loading direction parameter.

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• •The combined and interactive influences of crystallographic orientation, strain amplitude, cycle number, stacking fault energy and hydrogen doping on LCF behaviour of HMnSs are explored and discussed in detail.

Abstract

We studied the combined and interactive effects of crystallographic orientation, strain amplitude, cycle number, stacking fault energy (SFE) and hydrogen doping on the microstructure evolution of polycrystalline high-manganese steels (HMnSs) under low-cycle fatigue (LCF). An integrated experimental approach combining digital image correlation (DIC), electron backscatter diffraction (EBSD) and electron channelling contrast imaging (ECCI) at interrupted cycles was performed in the same region of interest on the bulk shear samples, which enables us to systematically compare the dislocation patterns of grains with defined loading conditions at a much larger field of view and less artefacts compared to transmission electron microscopy (TEM). We found that Taylor factor (M) works well with describing the effect of crystallographic orientation, which was further proved by the crystal plasticity finite element method (CPFEM). In detail, grains with a medium M value

Link

https://doi.org/10.1016/j.ijplas.2020.102803