High temperature decomposition and age hardening of single-phase wurtzite Ti\(_{1-x}\)Al\(_{x}\)N thin films grown by cathodic arc deposition

We investigated the high temperature decomposition behavior of wurtzite phase Ti\(_{1-x}\)Al\(_{x}\)N films using experimental methods and first-principles calculations. Single phase metastable wurtzite Ti\(_{1-x}\)Al\(_{x}\)N (x = 0.65, 0.75, 085 and 0.95) solid solution films were grown by cathodi...

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Published in:arXiv.org 2023-05
Main Authors: Salamania, J, Bock, F, Johnson, L J S, Tasnádi, F, K M Calamba Kwick, Farhadizaeh, A F, Abrikosov, I A, Rogström, L, Odén, M
Format: Article
Language:English
Subjects:
Age hardening
Aging (artificial)
Aluminum
Arc deposition
Elastic properties
First principles
High temperature
Mathematical analysis
Miscibility
Phase diagrams
Scanning transmission electron microscopy
Solid solutions
Spinodal decomposition
Substrates
Thin films
Titanium
Wurtzite
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Summary:We investigated the high temperature decomposition behavior of wurtzite phase Ti\(_{1-x}\)Al\(_{x}\)N films using experimental methods and first-principles calculations. Single phase metastable wurtzite Ti\(_{1-x}\)Al\(_{x}\)N (x = 0.65, 0.75, 085 and 0.95) solid solution films were grown by cathodic arc deposition using low duty cycle pulsed substrate-bias voltage. First-principles calculated elastic constants of the wurtzite Ti\(_{1-x}\)Al\(_{x}\)N phase show a strong dependence on alloy composition. The predicted phase diagram shows a miscibility gap with an unstable region. High resolution scanning transmission electron microscopy and chemical mapping demonstrate decomposition of the films after high temperature annealing (950\(^{\circ}\)C), which resulted in nanoscale chemical compositional modulations containing Ti-rich and Al-rich regions with coherent or semi coherent interfaces. This spinodal decomposition of the wurtzite film causes age hardening of 1-2 GPa.
ISSN:2331-8422