title: Contact-damage-resistant ceramic/single-wall carbon nanotubes and ceramic/graphite composites.
abstract: There has been growing interest in incorporating single-wall carbon nanotubes (SWNTs) as toughening agents in brittle ceramics. Here we have prepared dense Al(2)O(3)/SWNT composites using the spark-plasma sintering (SPS) method. Vickers (sharp) and Hertzian (blunt) indentation tests reveal that these composites are highly contact-damage resistant, as shown by the lack of crack formation. However, direct toughness measurements, using the single-edge V-notch beam method, show that these composites are as brittle as dense Al(2)O(3) (having a toughness of 3.22 MPa m(0.5)). This type of unusual mechanical behaviour was also observed in SPS-processed, dense Al(2)O(3)/graphite composites. We argue that the highly shear-deformable SWNTs or graphite heterogeneities in the composites help redistribute the stress field under indentation, imparting the composites with contact-damage resistance. These composites may find use in engineering and biomedical applications where contact loading is important.
authors.affiliation: Department of Metallurgy and Materials Engineering, Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269-3136, USA.
authors.forename: Xiaotong
authors.initials: X
authors.lastname: Wang
authors.forename: Nitin P
authors.initials: NP
authors.lastname: Padture
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Tanaka
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D004548:Elasticity; D006244:Hardness; D006245:Hardness Tests / Q000295:instrumentation / Q000379:methods; D008420:Manufactured Materials; D008422:Materials Testing / Q000295:instrumentation / Q000379:methods*; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D033081:Shear Strength; D013499:Surface Properties
chemical_list: D037742:Nanotubes, Carbon; D000537:Aluminum Oxide