Structure of nanocrystalline palladium and copper studied by small angle neutron scattering
- Materials Science and Engineering Department, Northwestern University, Evanston, Illinois 60208-3108 (United States)
- Cold Neutron Research Facility, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
The structure of nanocrystalline palladium and copper, made by inert gas condensation and compaction, was studied using small angle neutron scattering (SANS), optical microscopy, and scanning electron microscopy. The effects of annealing and warm compaction were also examined with these techniques. The SANS results were interpreted using a maximum entropy routine, combined with knowledge of the Archimedes density and hydrogen concentration determined by prompt gamma activation analysis (PGAA). Similar hydrogen concentrations were detected by SANS and PGAA. This hydrogen content, which was approximately 5 at.{percent} in samples compacted at room temperature, was reduced by both annealing and warm compaction. Defects in several size classes were observed, including missing grain pores ({approx_equal}1{endash}50 nm diameter) and defects of micrometer size. Warm compaction produced a lower number density of pores in nanocrystalline palladium, which led to increased density. The observed structure was correlated with Vickers microhardness and fracture surface morphology. {copyright} {ital 1996 Materials Research Society.}
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 432506
- Journal Information:
- Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 12 Vol. 11; ISSN JMREEE; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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