Kinetics and Mechanisms of Creep in Sintered Alpha Silicon Carbide and Niobium Carbide.

Abstract

Constant stress compressive creep studies and complementary TEM research have been conducted on sintered alpha-SiC and on dense polycrystalline NbCO737 to determine the kinetics and the mechanisms of deformation as a function of temperature and stress. In the former material, the values of the stress exponents of 1.44-1.71 indicate that either viscous flow or grain boundary sliding is controlling creep. However, the values of the activation energies (approx. 400kJ/mol below 1920K and approx. 850 kJ/mol above 1920K) coupled with the TEM studies which show the presence of considerable dislocation glide activity and the formation of corrugated grain boundaries and the formation of porosity on the boundaries and voids at the triple points. Originator supplied keywords include: Hot Isostatic pressing; Climb; Stacking faults; Diffusion.

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Document Details

Document Type
Technical Report
Publication Date
Sep 18, 1985
Accession Number
ADA161455

Entities

People

  • Robert F Davis

Organizations

  • North Carolina State University

Tags

Communities of Interest

  • Advanced Electronics
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Ceramic Materials
  • Chemical Vapor Deposition
  • Compound Semiconductors
  • Crystal Structure
  • Crystals
  • Electron Microscopy
  • Grain Boundaries
  • Heat Of Activation
  • High Temperature
  • Materials
  • Materials Engineering
  • Materials Science
  • Microscopy
  • Silicon Carbide
  • Single Crystals
  • Steady State
  • Transition Temperature

Readers

  • Materials Science and Engineering.
  • Organic Chemistry