Institute of Fundamental Technological Research
Polish Academy of Sciences

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Jakub Kawałko


Recent publications
1.  Nalepka K. T., Tabin J., Kawałko J., Brodecki A., Bała P., Kowalewski Z. L., Plastic Flow Instability in Austenitic Stainless Steels at Room Temperature: Macroscopic Tests and Microstructural Analysis, International Journal of Plasticity, ISSN: 0749-6419, DOI: 10.1016/j.ijplas.2024.104159, Vol.183, No.104159, pp.1-18, 2024

Abstract:
AISI 304 steel experiences plastic flow instability during tension at room temperature if appropriate conditions are applied: a low strain rate and a sufficiently long gauge section of the sample. Then, propagation of the strain-localised band is activated. The electron backscattered diffraction (EBSD) research revealed that the reason is not only the difference in the content of the secondary phase – martensite α’ across the front face, but also the change in the volume fraction of austenite grains with Copper (Cu) and Goss-Brass (GB) orientation. Consequently, there is a division between two areas of high and limited deformation capacity. The tendency to maintain the continuity of deformation fields induces a massive rotation of austenite grains to Cu and GB orientations, which then undergo shearing and phase transformation. As a result, momentary strain accumulation leaves behind a stiffer zone. It is shown that the trapping of austenite grains prone to large deformations, inside the matrix with Cu and GB orientations, makes the formation of a plastic strain front possible. These features improve the ductility and strength of the 304 steel over 316L and 316LN at room temperature. The in-situ EBSD tension studies for the considered grades reveal three developing textures, with their comparison showing a gradual decrease in the preferences of the Cu and GB components. Thus, the appearing bands of the accumulated strains in 316L are limited by the Cu and GB areas, while such blockages do not occur in 316LN. The presented strengthening mechanism is confirmed by the digital image correlation (DIC) measurements. The root-mean-square (RMS) function of strains along the tensile direction, characterising the linear surroundings of the considered point, is introduced as a tool for linking the micro and macro scales. The experimental results provide a basis for explaining discontinuous front propagation at a temperature near 0 K.

Keywords:
Plastic flow instability, Martensitic transformation, Austenitic stainless steels, RMS strain amplitude

Affiliations:
Nalepka K. T. - other affiliation
Tabin J. - IPPT PAN
Kawałko J. - other affiliation
Brodecki A. - IPPT PAN
Bała P. - AGH University of Science and Technology (PL)
Kowalewski Z. L. - IPPT PAN
2.  Tabin J., Nalepka K.T., Kawałko J., Brodecki A., Bała P., Kowalewski Z.L., Plastic Flow Instability in 304 Austenitic Stainless Steels at Room Temperature, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-023-07223-5, pp.1-6, 2023

Abstract:
A remarkable plastic flow instability is observed during tensile deformation of the commercial 304 stainless-steel sheet at room temperature. It has been found that the occurrence of plastic flow instability in 304 is dependent on the strain rate and specimen gage length. Moreover, it is essentially the same as the necking caused by plastic instability in 316L. However, the enhanced strain hardening resulting from deformation-induced martensitic transformation facilitates the orderly propagation of the strain-localized band.

Affiliations:
Tabin J. - IPPT PAN
Nalepka K.T. - other affiliation
Kawałko J. - other affiliation
Brodecki A. - IPPT PAN
Bała P. - AGH University of Science and Technology (PL)
Kowalewski Z.L. - IPPT PAN
3.  Kowalczyk-Gajewska K., Sztwiertnia K., Kawałko J., Wierzbanowski K., Wroński M., Frydrych K., Stupkiewicz S., Petryk H., Texture evolution in titanium on complex deformation paths: Experiment and modelling, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2015.04.040, Vol.637, pp.251-263, 2015

Abstract:
Texture evolution in commercially pure titanium deformed by equal-channel angular pressing (ECAP) and extrusion with forward–backward rotating die (KoBo) is studied both experimentally and numerically. New results are provided that demonstrate the effects of distinct and complex deformation paths on the texture in the ultra-fine grained (UFG) material obtained after severe plastic deformation (SPD). The numerical simulations are based on the self-consistent viscoplastic method of grain-to-polycrystal scale transition. A recently proposed modification of the probabilistic scheme for twinning is used that provides consistent values of the twin volume fraction in grains. The basic components of the experimentally observed texture are reasonably well reproduced in the modelling. The numerical simulations provide an insight into the internal mechanisms of plastic deformation, revealing substantial activity of mechanical twinning in addition to the basal and prismatic slip in titanium processed by ECAP.

Keywords:
Texture evolution, UFG materials, SPD processes, Crystal plasticity, Twinning

Affiliations:
Kowalczyk-Gajewska K. - IPPT PAN
Sztwiertnia K. - other affiliation
Kawałko J. - other affiliation
Wierzbanowski K. - other affiliation
Wroński M. - other affiliation
Frydrych K. - IPPT PAN
Stupkiewicz S. - IPPT PAN
Petryk H. - IPPT PAN

Conference abstracts
1.  Tabin J., Brodecki A., Kowalewski Z., Kawałko J., Bała P., Nalepka K., Plastic Flow Instability in Austenitic Stainless Steels at a Wide Range of Temperatures: From Macroscopic Tests to Microstructural Analysis, SPAS 2024, Superconductivity & Particle Accelerators conference, 2024-10-21/10-24, Kraków (PL), No.106, pp.34-34, 2024
2.  Tabin J., Brodecki A., Kowalewski Z., Nalepka K., Kawałko J., Bała P., PLASTIC FLOW INSTABILITY IN AUSTENITIC STAINLESS STEELS AT A WIDE RANGE OF TEMPERATURES: FROM MACROSCOPIC TESTS TO MICROSTRUCTURAL ANALYSIS, ICEC/ICMC, 29th International Cryogenic Engineering Conference, International Cryogenic Materials Conference, 2024-07-22/07-26, Geneva (CH), No.2,2, pp.1-1, 2024
3.  Schob D., Tabin J., Kawałko J., Maasch P., Roszak R., Richter L., Kowalewski Z., Ziegenhorn M., DEFORMATION-INDUCED MARTENSITIC TRANSFORMATION IN FUSED FILAMENT FABRICATED AUSTENITIC STAINLESS STEELS DURING TENSION AT WIDE RANGE OF TEMPERATURES. PART 2: NUMERICAL SIMULATION, SolMech 2024, 43rd Solid Mechanics Conference, 2024-09-16/09-18, Wrocław (PL), pp.52-52, 2024

Keywords:
Phase transformation, Deformation-induced martensitic transformation, 316L, Fused Deposition Modelling

Affiliations:
Schob D. - other affiliation
Tabin J. - IPPT PAN
Kawałko J. - other affiliation
Maasch P. - other affiliation
Roszak R. - other affiliation
Richter L. - other affiliation
Kowalewski Z. - IPPT PAN
Ziegenhorn M. - other affiliation
4.  Tabin J., Schob D., Kawałko J., Brodecki A., Ranachowski Z., Maasch P., Roszak R., Ziegenhorn M., Kowalewski Z., DEFORMATION-INDUCED MARTENSITIC TRANSFORMATION IN FUSED FILAMENT FABRICATED AUSTENITIC, SolMech 2024, 43rd Solid Mechanics Conference, 2024-09-16/09-18, Wrocław (PL), pp.51-51, 2024

Keywords:
Deformation-induced martensitic transformation, Austenitic Stainless Steel, Additive Manufacturing, DIC, Cryogenic temperatures

Affiliations:
Tabin J. - IPPT PAN
Schob D. - other affiliation
Kawałko J. - other affiliation
Brodecki A. - IPPT PAN
Ranachowski Z. - IPPT PAN
Maasch P. - other affiliation
Roszak R. - other affiliation
Ziegenhorn M. - other affiliation
Kowalewski Z. - IPPT PAN
5.  Tabin J., Brodecki A., Kowalewski Z.L., Nalepka K., Kawałko J., Bała P., PLASTIC FLOW INSTABILITY IN AUSTENITIC STAINLESS STEELS AT A WIDE RANGE OF TEMPERATURES: FROM MACROSCOPIC TESTS TO MICROSTRUCTURAL ANALYSIS, DAS 2024, 40th DANUBIA-ADRIA SYMPOSIUM on Advances in Experimental Mechanics, 2024-09-24/09-27, Gdańsk (PL), pp.1-2, 2024

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