FACTORS AFFECTING THE HIGH TEMPERATURE STRENGTH OF POLYCRYSTALLINE SOLIDS

Abstract

Quantitative analyses of the high temperature strength data on pure polycrystalline metals indicate that the following factors will promote the high temperature creep resistance: (a) crystal structure; the best structure is the diamondtype, followed by the close-packed fcc or hcp structures and lastly, the bcc structure, (b) high melting temperature, (c) high elastic modulus, (d) high valence state, and (e) fine stable grain size. Comparison of current theories of high temperature deformation with experimental data reveal that Weertman's theory of creep based on dislocation climb best describes the experimental data for creep of pure metals at high stresses and the Nabarro-Herring theory based on atomic diffusion appears applicable at low stresses. (Author)

Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1961
Accession Number
AD0272146

Entities

People

  • Oleg D. Sherby

Organizations

  • Stanford University

Tags

DTIC Thesaurus Topics

  • Crystal Structure
  • Crystals
  • Diffusion
  • Dislocations
  • Experimental Data
  • Grain Size
  • High Temperature
  • Modulus Of Elasticity
  • Polycrystals
  • Resistance

Readers

  • Materials Science and Engineering.