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Grant NCN UMO-2023/49/B/ST11/00774 – OPUS 25

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Project Title

Investigation of stress states and elastic-plastic deformation mechanisms for polycrystalline grains using novel experimental methodologies and multiscale modeling

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Project Director

Prof. dr hab. inż. Andrzej Baczmański

Faculty of Physics and Applied Computer Science

AGH – University of Science and Technology

Address: al. Mickiewicza 30, 30-059 Krakow, Poland

Office: Room 317, Building D10

Email: baczman@agh.edu.pl

Abstract

The macroscopic elastic-plastic properties of polycrystalline materials depend on chemical composition, microstructure, phase composition, crystal structure, and crystallographic texture. These characteristics directly affect mechanisms of plastic deformation at the mesoscale, i.e., the scale of polycrystalline grains. Developing experimental methodologies to study material behavior at this scale is therefore essential. Knowledge of plastic processes at the grain level is necessary to understand and describe macroscopic properties such as hardness, hardening, and elastic-plastic behavior.

Special attention is paid to two-phase and composite materials, which are unique from the point of view of their mechanical properties, combining features of constituent phases. Investigating each phase is challenging; diffraction methods allow selective, non-destructive measurement of lattice strains and their evolution. The displacement of diffraction peaks provides detailed information about individual crystallites. Combining diffraction experiments with self-consistent modeling enables study of active slip systems, twinning, and stress evolution during deformation.

Elastoplastic deformation depends on grain-level phenomena such as slips, twinning, and detwinning. Determining critical resolved shear stresses (CRSS) for slip and twinning activation is crucial, as these processes are driven by localized stresses. Interactions between grains and crystallographic texture further influence overall mechanical behavior. Previously, stress localization was studied with elastoplastic models, but assumptions about intergranular interactions introduced uncertainties. Our methodologies allow direct experimental determination of stresses at the grain scale, including for two-phase materials and complex loading paths.

The main goal of this project is to advance and apply these original methodologies to study complex materials such as two-phase alloys and metal matrix composites, to validate elastoplastic self-consistent models, and to link phenomena across scales. This will allow prediction of complex elastic-plastic deformation for materials with varying crystallographic textures.

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Conferences & Presentations