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Journal of Materials Science

, Volume 9, Issue 3, pp 349–358 | Cite as

Hardness anisotropy in niobium carbide

  • G. Morgan
  • M. H. Lewis
Papers

Abstract

Measurements of hardness anisotropy by Knoop diamond indentation on the {100} surfaces of Nb6C5 crystals show that the hardness is determined by crystallographic slip on {111} 〈1¯10〉 and {110} 〈1¯10〉 systems. {111} is the preferred slip plane for Nb6C5 and crystals with higher carbon content which show a marked decrease in Knoop hardness. The carbon atom/vacancy arrangement in these crystals is shown, by electron diffraction, to possess short-range order. Crystals annealed at low temperatures contain domains of non-cubic long-range order which increase the Knoop hardness and eliminate the anisotropy in hardness. Dislocation arrangements around Knoop indentations have been directly observed by electron microscopy in an attempt to confirm the slip processes deduced from hardness anisotropy.

Keywords

Anisotropy Carbide Niobium Electron Diffraction Slip Plane 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman and Hall 1974

Authors and Affiliations

  • G. Morgan
    • 1
  • M. H. Lewis
    • 1
  1. 1.Department of PhysicsUniversity of WarwickCoventryUK

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