Alicja Trzepacz1*, M. Marciszko-Wiąckowska2**, A. Baczmański1, W. Bednarczyk3, S. Wroński1, K. Wierzbanowski1

 

1 AGH University of Krakow, Faculty of Physics and Applied Computer Science, al. Mickiewicza 3, 30-059 Kraków, Poland,

2 AGH University of Krakow, Academic Centre for Materials and Nanotechnology, al. Mickiewicza 30, 30-059 Kraków, Poland,

3 AGH University of Krakow, Faculty of Metals and Industrial Computer Science, al. A. Mickiewicza 30, 30-059 Kraków, Poland.

 

* atrzepacz@student.agh.edu.pl

**marciszk@agh.edu.pl

 

 

Reliable residual stress evaluation in polycrystalline materials requires the selection of an appropriate grain-interaction model that consistently links experimentally measured lattice strains with the corresponding macroscopic stress state. In this work, the near-surface stress state of mechanically polished austenitic steel with a very fine grain size of approximately 3 μm was investigated. Several classical grain-interaction models were examined, and the model that reproduced the best the experimentally observed response in the subsurface region was selected for the further analysis.

To study the mechanical response, a bending machine was used, and the stress state was calculated for several applied loads. Intergranular elastic interactions together with second-order plastic incompatibility stress in austenitic steel were analyzed using diffraction-based methods. Lattice strains were measured within the material using a multiple-reflection approach in the angle-dispersive X-ray diffraction during in-situ bending experiments. The verified X-ray Stress Factors (XSFs) enabled investigation of the depth-dependent evolution of both the first- and the second-order stresses.

The results demonstrate that elastic anisotropy alone cannot account for the observed non-linearities in the sin²ψ plots, and that crystallographic texture is insufficient to explain this behavior. Consequently, a more advanced interpretation framework based on elastic-plastic self-consistent (EPSC) modeling is required. Application of EPSC made it possible to rationalize the non-linear sin²ψ dependencies and to determine the corresponding evolutions of the first- and  the second-order stresses.

Acknowledgements: This work was financed by the grant from the National Science Centre, Poland (NCN), No. UMO-2023/49/B/ST11/00774. The research project was also partly supported by the programme ‘Excellence Initiative – Research University’ for the AGH University of Science and Technology, Krakow, Poland.

 

References

[1] M.Marciszko-Wiąckowska, A. Oponowicz, A. Baczmański, Ch. Braham, M. Wątroba, M. Wróbel, M. Klaus, Ch. Genzel Measurement, 2022, 194, 111016, 1-21.

[2] M. Marciszko-Wiąckowska, A. Baczmański, D. Apel, M. Klaus, Ch. Genzel, M. Chemkhi, M. Saferna, K. Wierzbanowski, J. Kawałko, L. Le Joncour, M. Francis, P. Bała Journal of Applied Crystallography, 2025, 58.