@misc{bcke_decomposition_pathways_2023, 
author={Bäcke, O.,Kalbfleisch, S.,Stiens, D.,Manns, T.,Davydok, A.,Halvarsson, M.,Hörnqvist Colliander, M.},
title={Decomposition pathways in nano-lamellar CVD Ti0.2Al0.8N},
year={2023},
howpublished = {journal article},
doi = {https://doi.org/10.1016/j.mtla.2023.101833},
abstract = {Recent progress in chemical vapour deposition (CVD) technology has enabled synthesis of metastable cubic TiAlN coatings with as high as 0.8–0.9. These coatings have unique micro- and nano-structures consisting of grains with epitaxially grown nanolamellae with different Al/Ti ratios, and exhibit exceptional hardness and resistance to wear and oxidation. Here, the thermal stability and decomposition of nano-lamellar CVD Ti0.2Al0.8N at temperatures between 800 and 1000 °C have been investigated using a combination of cross-sectional transmission X-ray nano-diffraction and scanning transmission electron microscopy. The decomposition started by formation of hexagonal AlN (h-AlN) in the grain boundaries throughout the coating. Below 900 °C, only limited further decomposition of the grain interiors occurred. At higher temperatures the formation of grain boundary h-AlN was followed by a bulk transformation of the nano-lamellar structure, starting at the top of the coating and subsequently sweeping inwards. The bulk transformation occurred initially through spinodal decomposition, followed by transformation of the Al-rich cubic phase to h-AlN, leading to a coarsened structure with Ti-rich domains in a h-AlN matrix. The behaviour is explained by the higher capability of grain boundaries and free surfaces to accommodate the volumetric expansion from the h-AlN formation. The results increase our understanding of the complicated decomposition processes in these metastable cubic coatings, which are of utmost importance from both technological and scientific perspectives.},
note = {Online available at: \url{https://doi.org/10.1016/j.mtla.2023.101833} (DOI). Bäcke, O.; Kalbfleisch, S.; Stiens, D.; Manns, T.; Davydok, A.; Halvarsson, M.; Hörnqvist Colliander, M.: Decomposition pathways in nano-lamellar CVD Ti0.2Al0.8N. Materialia. 2023. vol. 30, 101833. DOI: 10.1016/j.mtla.2023.101833}}