Early stage spinodal decomposition and microstructure evolution in TiAlN: A combined in-situ SAXS and phase field study
(English)Manuscript (preprint) (Other academic)
This paper describes in detail the microstructure and phase evolution in Ti0.33Al0.67N and Ti0.50Al0.50N coatings during isothermal annealing, studied by in-situ small angle x-ray scattering (SAXS), in combination with phase field simulations. We show that the isostructural spinodal decomposition occurs in two stages. During the initial stage, the phase segregation proceeds with a constant size of AlN- and TiN-rich domains with an experimentally measured radius of ~0.7 nm for 5 and 20 min at 900 and 850 °C respectively in the Ti0.50Al0.50N alloy. The length of the initial stage depends on temperature as well as metal composition, and is shorter for the higher Al-content coating. After the initial stage, the coherent cubic AlN- and TiN-rich domains coarsen. The coarsening process is kinetically limited by diffusion, which allowed us to estimate the diffusivity and activation energies of the metals to 1.4·10-7 m2s-1 and 3.14 eV at-1 respectively.
TiAlN, Phase-field simulations, Spinodal decomposition, SAXS, High energy x-ray diffraction, Coarsening
IdentifiersURN: urn:nbn:se:liu:diva-79607OAI: oai:DiVA.org:liu-79607DiVA: diva2:543917