TY - JOUR
T1 - Mechanical properties and microstructures of metal/ceramic microlaminates
T2 - Part I. Nb/MoSi2 systems
AU - Chou, T. C.
AU - Nieh, T. G.
AU - Tsui, T. Y.
AU - Pharr, G. M.
AU - Oliver, W. C.
N1 - Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].
PY - 1992/10
Y1 - 1992/10
N2 - Artificial multilayers, or microlaminates, composed of alternating layers of Nb and MoSi2 of equal thickness were synthesized by d.c., magnetron sputtering. Four different modulation wavelengths, λ, were studied: 7, 11, 20, and 100 nm. The compositions, periodicities, and microstructures of the microlaminates were characterized by Auger electron spectroscopy and transmission electron microscopy. Structural characterization revealed that the as-deposited Nb layers are polycrystalline, while the MoSi2 layers are amorphous. The hardnesses and elastic moduli of the films were measured using nanoindentation techniques. Neither a supermodulus nor a superhardness effect could be identified in the range of wavelengths investigated; for each of the microlaminates, both the hardness and modulus were found to fall between the bounds set by the properties of the monolithic Nb and MoSi2 films. Nevertheless, a modest but a measurable increase in both hardness and modulus with decreasing wavelength was observed, thus indicating that behavior cannot be entirely described by a simple rule-of-mixtures. The hardness was found to vary linearly with Δ-1/2 in a manner similar to the Hall-Petch relationship. Annealing the microlaminates at 800 °C for 90 min produces significant increases in hardness and modulus due to chemical interaction of the layers. © 1992, Materials Research Society. All rights reserved.
AB - Artificial multilayers, or microlaminates, composed of alternating layers of Nb and MoSi2 of equal thickness were synthesized by d.c., magnetron sputtering. Four different modulation wavelengths, λ, were studied: 7, 11, 20, and 100 nm. The compositions, periodicities, and microstructures of the microlaminates were characterized by Auger electron spectroscopy and transmission electron microscopy. Structural characterization revealed that the as-deposited Nb layers are polycrystalline, while the MoSi2 layers are amorphous. The hardnesses and elastic moduli of the films were measured using nanoindentation techniques. Neither a supermodulus nor a superhardness effect could be identified in the range of wavelengths investigated; for each of the microlaminates, both the hardness and modulus were found to fall between the bounds set by the properties of the monolithic Nb and MoSi2 films. Nevertheless, a modest but a measurable increase in both hardness and modulus with decreasing wavelength was observed, thus indicating that behavior cannot be entirely described by a simple rule-of-mixtures. The hardness was found to vary linearly with Δ-1/2 in a manner similar to the Hall-Petch relationship. Annealing the microlaminates at 800 °C for 90 min produces significant increases in hardness and modulus due to chemical interaction of the layers. © 1992, Materials Research Society. All rights reserved.
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U2 - 10.1557/JMR.1992.2765
DO - 10.1557/JMR.1992.2765
M3 - RGC 21 - Publication in refereed journal
SN - 0884-2914
VL - 7
SP - 2765
EP - 2773
JO - Journal of Materials Research
JF - Journal of Materials Research
IS - 10
ER -