Microstructure, mechanical properties and wear resistance of WC/Co nanocomposites
- Stevens Inst. of Tech., Hoboken, NJ (United States). Dept. of Materials Science and Engineering
The microstructure, mechanical properties, abrasion and wear resistance of WC-Co nanocomposites synthesized by the spray conversion technique by McCaundlish, Kear and Kim have been investigated. The binder phase of WC-Co nanocomposites is enriched in W and C, compared to conventional cermets. Small amorphous regions exist in the binder despite the slow cooling after liquid phase sintering. Few dislocations are found in the WC grains. The increased WC content and the amorphous regions modify (i.e. strengthen) the binder phase of the composites. Vickers indentation measurements show a hardness of the nanocomposites reaching 2,310 kg/mm{sup 2}. While the toughness of conventional cermets decreases with increasing hardness, the toughness does not decrease further as the WC grain size decreases from 0.7 to 0.07 {micro}m but remains constant at 8 MPam{sup 1/2}. Scratches caused by a diamond indenter are small, commensurate with their hardness. These scratches are ductile, devoid of the grain fracture that is observed with conventional materials. The abrasions resistance of nanocomposites is about double that of conventional materials, although their hardness is larger by 23% only. This is due to the lack of WC grain fragmentation and removal which takes place in conventional cermets. Sliding wear resistance of WC/Co is proportional to their hardness; no additional benefit of nanostructure is obtained. This results from the very small size of adhesive wear events in even large WC grains.
- OSTI ID:
- 522320
- Report Number(s):
- CONF-961202-; ISBN 1-55899-361-4; TRN: 97:014715
- Resource Relation:
- Conference: 1996 Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 2-6 Dec 1996; Other Information: PBD: 1997; Related Information: Is Part Of Nanophase and nanocomposite materials 2; Komarneni, S. [ed.] [Pennsylvania State Univ., University Park, PA (United States)]; Parker, J.C. [ed.] [Nanophase Technologies Corp., Burr Ridge, IL (United States)]; Wollenberger, H.J. [ed.] [Hahn-Meitner Inst., Berlin (Germany)]; PB: 573 p.; Materials Research Society symposium proceedings, Volume 457
- Country of Publication:
- United States
- Language:
- English
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