Complex temperature dependent behaviour revealed by in-situ heating experiments on single crystals of deformed halite: New ways to recognize and evaluate annealing in geological materials
2010 (English)In: Journal of Structural Geology, ISSN 0191-8141, Vol. 32, no 7, 982-996 p.Article in journal (Refereed) Published
The dynamics of substructures, which encompass all structures present at the subgrain-scale, were investigated by static, in-situ annealingexperiments. Deformed, single crystalhalite was annealed inside a scanning electron microscope at temperatures between 280 and 470 °C. Electron backscatter diffraction maps provided detailed information about crystallographic orientation changes. Three temperature dependent regimes were distinguished based on boundary misorientation changes. In regime I (280–300 °C) some low angle boundaries (LABs), i.e. with 1°–15° misorientation, increase in misorientation angle, while others decrease. In regime II (∼300 °C) all LABs undergo a decrease in misorientation angle. Regime III (>300 °C) is defined by enhancement of the subgrain structure as remaining LABs increase and some undergo a rotation axis change. Throughout regimes I and II, new LABs develop, subdividing subgrains. LABs could be divided into four categories based on annealingbehaviour, orientation and morphology. We suggest that these observations can be directly related to the mobility and activation temperature of climb of two dislocation groups introduced during deformation. Therefore, with in-depth investigation of a substructure with known deformation geometry, we can infer ratios of dislocation types and their post-deformation and post-annealing location. These can potentially be used to estimate the post-deformational annealing temperature in crystalline materials.
Place, publisher, year, edition, pages
2010. Vol. 32, no 7, 982-996 p.
Halite; Annealing; EBSD; Substructure; In-situ
Research subject Geology
IdentifiersURN: urn:nbn:se:su:diva-33137DOI: 10.1016/j.jsg.2010.06.006OAI: oai:DiVA.org:su-33137DiVA: diva2:282423