arXiv subjects

Håkon W. Ånes

Publications and source records attributed to Håkon W. Ånes.

3 recordsLinked to original sources

arXiv2026

kikuchipy: an open-source toolbox for analysis of EBSD patterns

We present kikuchipy, an open-source toolbox for analysis of electron backscatter diffraction patterns, written in Python. The software is capable of both Hough and dictionary indexing and orientation and/or projection center refinement of patterns stored in file formats from all major vendors. Indexing results can be validated using maps independent of indexing and by visually comparing experimental and simulated patterns. By leveraging scientific packages in the Python ecosystem, emphasis is put on making the indexing workflow flexible and improve results through fast iteration. The software's capabilities are demonstrated on three application examples: analysis of orientation relationships in a super duplex stainless steel, phase differentiation of aluminium and silicon in a cast modified Al-Si alloy, and phase differentiation of particles in an Al-Mn alloy as Al6Mn or alpha-AlMnSi. The diffraction patterns and analysis workflows are made publicly available. kikuchipy was created and is developed as a resource for the electron microscopy community, allowing anyone to improve the software or include it into their own analysis workflows or softwares.

cond-mat.mtrl-sci↗

arXiv2022

Orientation dependent pinning of (sub)grains by dispersoids during recovery and recrystallization in an Al-Mn alloy

The recrystallized grain size and texture in alloys can be controlled via the microchemistry state during thermomechanical processing. The influence of concurrent precipitation on recovery and recrystallization is here analyzed by directly correlating (sub)grains of P, CubeND or Cube orientation with second-phase particles in a cold-rolled and non-isothermally annealed Al-Mn alloy. The recrystallized state is dominated by coarse elongated grains with a strong P, weaker CubeND and even weaker Cube texture. The correlated data enables orientation dependent quantification of the density and size of dispersoids on sub-boundaries and subgrains in the deformation zones around large constituent particles. A new modified expression for the Smith-Zener drag from dispersoids on sub-boundaries is derived and used. The results show that the drag on (sub)grain boundaries from dispersoids is orientation dependent, with Cube subgrains experiencing the highest drag after recovery and partial recrystallization. The often observed size advantage of Cube subgrains in Al alloys is not realized due to the increased drag, thereby promoting particle-stimulated nucleation (PSN). Relatively fewer and larger dispersoids in deformation zones around large particles give a reduced Smith-Zener drag on PSN nuclei, thus further strengthening the effect of PSN. Observations substantiating the stronger P texture compared to the CubeND texture are a higher frequency of P subgrains and a faster growth of these subgrains. The applied methodology enables a better understanding of the mechanisms behind the orientation dependent nucleation and growth behavior during recovery and recrystallization with strong concurrent precipitation in Al-Mn alloys. In particular, the methodology gives new insights into the strong P and CubeND textures compared to the Cube texture.

cond-mat.mtrl-sci↗

arXiv2022

Confinement-driven inverse domain scaling in polycrystalline ErMnO3

The research on topological phenomena in ferroelectric materials has revolutionized the way we understand polar order. Intriguing examples are polar skyrmions, vortex/anti-vortex structures and ferroelectric incommensurabilties, which promote emergent physical properties ranging from electric-field-controllable chirality to negative capacitance effects. Here, we study the impact of topologically protected vortices on the domain formation in improper ferroelectric ErMnO3 polycrystals, demonstrating inverted domain scaling behavior compared to classical ferroelectrics. We observe that as the grain size increases, smaller domains are formed, which we relate to the interaction of the topological vortices with local strain fields. The inversion of the domain scaling behavior has far-reaching implications, providing fundamentally new opportunities for topology-based domain engineering and the tuning of the electromechanical and dielectric performance of ferroelectrics in general.

cond-mat.mtrl-sci↗