Mechanical behavior of nanocrystalline Cu and Pd
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (USA)
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (USA)
This report gives results of a study of the bulk mechanical properties of samples of nanocrystalline Cu and Pd consolidated from powders prepared by inert gas condensation. Fourier analysis x-ray diffraction techniques, used to determine average grain size and mean lattice strains of the as-consolidated samples, show grain sizes in the range of 3--50 nm and lattice strains ranging from 0.02--3%. Sample densities range from 97--72% of the density of a coarse-grained standard. Microhardness of the nanocrystalline samples exceeds that of annealed, coarse-grained samples by a factor of 2--5, despite indications that sample porosity reduces hardness values below the ultimate value. Uniaxial tensile strength of the nanocrystalline samples is similarly elevated above the value of the coarse-grained standard samples. Restrictions on dislocation generation and mobility imposed by ultrafine grain size are believed to be the dominant factor in raising strength. Residual stress may also play a role. Room temperature diffusional creep, predicted to be appreciable in nanocrystalline samples, was not found. Instead, samples appear to show logarithmic creep that is much smaller than the predicted Coble creep.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 5493800
- Journal Information:
- Journal of Materials Research; (USA), Vol. 6:5; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COPPER
MECHANICAL PROPERTIES
SINTERING
PALLADIUM
DISLOCATIONS
FOURIER ANALYSIS
POWDERS
STRAINS
X-RAY DIFFRACTION
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFRACTION
ELEMENTS
FABRICATION
LINE DEFECTS
METALS
PLATINUM METALS
SCATTERING
TRANSITION ELEMENTS
360103* - Metals & Alloys- Mechanical Properties