Super hardening and deformability in epitaxially grown W/NbN nanolayers under shallow and deep nanoindentations

Autor:	Scott X. Mao, Anita Madan, Scott A. Barnett, B. M. Ennis, William S. Slaughter
Rok vydání:	2003
Předmět:	Niobium nitride Materials science Bilayer Superlattice General Physics and Astronomy chemistry.chemical_element Tungsten Epitaxy chemistry.chemical_compound Crystallography chemistry visual_art Indentation visual_art.visual_art_medium Hardening (metallurgy) Ceramic Composite material
Zdroj:	Journal of Applied Physics. 94:6892-6898
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.1621083
Popis:	Epitaxially grown W/NbN nanolayers are superlattice materials that exhibit a hardness at small bilayer repeat periods which exceed the hardness predicted by the rule of mixtures for normal composites. Interfaces in the bilayered superlattice play a critical role in the superhardening process. The objective of this investigation was to examine the behavior of the superlattice material, W/NbN. Nanoindentations and in situ surface imaging were conducted over a range of applied loads on samples of W/NbN with two different bilayer periods (Λ=5.6 and 10.4 nm), and monolithic samples of the niobium nitride (NbN) ceramic and the tungsten (W) metal which comprise the superlattice material. Shallow nanoindentations were made to a depth equal to the individual layer thicknesses of the epitaxially grown W/NbN nanolayers in order to investigate the individual interface effect. The mechanical properties were determined using the Oliver and Pharr method and compared for all the samples. The energies of indentation are c...
Databáze:	OpenAIRE
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