Thermally induced age hardening in tough Ta-Al-N coatings via spinodal decompositionShow others and affiliations
2017 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, no 15, article id 155304Article in journal (Refereed) Published
Abstract [en]
We combine experiments and ab initio density functional theory calculations to investigate the evolution in structural and mechanical properties of TaAlN coatings as a function of the annealing temperature T. Formation of coherent cubic TaN- and AlN-rich nanometer-size domains, occurring during the initial stage of thermally induced phase separation within cubic NaCl-type (B1) TaAlN solid solutions, yields a monotonic increase in hardness from 29 GPa (as deposited coatings) up to a maximum of 35 GPa (+17%) reached after annealing at 1000 degrees C. Further thermal treatment at T amp;gt; 1000 degrees C leads to the transformation of metastable cubic domains into stable hexagonal TaNx and wurtzite AlN phases, thus resulting in hardness reductions. A comparison of our results with those reported in the literature reveals that TaAlN coatings are at least as hard while considerably less stiff (lower elastic moduli) than TiAlN coatings, thus indicating a substantial increase in toughness achieved upon replacing Ti with Ta in the host lattice. Present findings suggest that cubic TaAlN solid solutions are promising candidates for applications in protective coatings possessing both high-temperature hardness and toughness. Published by AIP Publishing.
Place, publisher, year, edition, pages
AMER INST PHYSICS , 2017. Vol. 121, no 15, article id 155304
National Category
Manufacturing, Surface and Joining Technology
Identifiers
URN: urn:nbn:se:liu:diva-137606DOI: 10.1063/1.4981534ISI: 000399903200029OAI: oai:DiVA.org:liu-137606DiVA, id: diva2:1097365
Note
Funding Agencies|Slovak Research and Development Agency [APVV-14-0173]; Operational Program Research and Development [ITMS 26210120010]; Ministry of Education, Science, Research and Sport of the Slovak Republic within the Research and Development Operational Programme for the project "University Science Park of STU Bratislava" [ITMS 26240220084]; European Regional Development Fund; Olle Engkvist Foundation
2017-05-222017-05-222019-06-28