Mechanical properties and microstructures of metal/ceramic microlaminates: Part II. A Mo/Al sub 2 O sub 3 system

Journal Article · Thu Oct 01 00:00:00 EDT 1992 · Journal of Materials Research; (United States)

DOI:https://doi.org/10.1557/JMR.1992.2774· OSTI ID:7080711

Chou, T C; Nieh, T G ^[1]; McAdams, S D; Pharr, G M ^[2]; Oliver, W C ^[3]

---

1. Lockheed Missiles and Space Company, Inc., Research and Development Division, O/93-10, B/204, Palo Alto, California 94304 (United States)
2. Department of Materials Science, Rice University, P.O. Box 1892, Houston, Texas 77251 (United States)
3. Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6116 (United States)

Synthetic multilayers consisting of periodic layers of the refractory metal Mo and the oxide ceramic Al{sub 2}O{sub 3} have been produced by alternating d.c. and r.f. reactive sputter deposition. Microlaminates with four different modulation wavelengths{minus}5, 20, 30, and 100 nm{minus}were investigated in this study. The compositions, periodicities, and microstructures of the microlaminates were characterized by Auger electron spectroscopy, low-angle x-ray diffraction, and transmission electron microscopy, including high resolution lattice imaging and microdiffraction. Transmission electron microscopy from the microlaminates indicated that the as-deposited Mo layers are polycrystalline, while the as-deposited Al{sub 2}O{sub 3} layers are primarily amorphous. The Mo and Al{sub 2}O{sub 3} layers are thermally compatible at 800 {degree}C for 6 h, showing no evidence of atomic interdiffusion between the layers. The mechanical properties of the microlaminates, as well as those of monolithic films of Mo and Al{sub 2}O{sub 3} (i.e., the baseline materials), were investigated using nanoindentation methods. A higher than expected modulus and hardness were observed for the microlaminate with the longest wavelength (100 nm); otherwise the mechanical properties are explainable by a rule-of-mixtures. The enhanced mechanical properties of the 100 nm microlaminate may be attributed to crystallization of the amorphous Al{sub 2}O{sub 3} layers and the evolution of a structural texture within this phase.

• DOE Contract Number: AC05-84OR21400; AC05-76OR00033
• OSTI ID: 7080711
• Journal Information: Journal of Materials Research; (United States), Vol. 7:10; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
MECHANICAL PROPERTIES
MOLYBDENUM
AMORPHOUS STATE
AUGER ELECTRON SPECTROSCOPY
HARDNESS
LAYERS
MICROSTRUCTURE
POLYCRYSTALS
SPUTTERING
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
ALUMINIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
CRYSTAL STRUCTURE
CRYSTALS
DIFFRACTION
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTS
METALS
MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
SCATTERING
SPECTROSCOPY
TRANSITION ELEMENTS
360602* - Other Materials- Structure & Phase Studies
360603 - Materials- Properties