Interaction of Two Slip Planes on Extrusion Growth in Fatigue Band

Abstract

Micromechanic theory of fatigue crack initiation by Lin and his associates is reviewed. Intrusions and extensions have been observed in fatigue specimens. An initial stress field favorable for the growth of extrusion or intrusion can be produced by arrays of dislocation dipoles as shown by Lin (1969). These dipoles caused an initial tensile strain giving an elongation which is called the static extrusion growth terminates. Along the direction of an extrusion, tensile strain and tensile stress occurs. The tensile stress caused the resolved shear stress to reach critical and slide in a secondary slip system. The slip causes plastic tensile strain which increases significantly the extrusion growth. Similarly the same mechanism exists for the growth of intrusions. This explains why extrusions grows much more than the static extrusion.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1987
Accession Number
ADA182288

Entities

People

  • S. R. Lin
  • T. H. Lin
  • Xiaoqin Wu

Organizations

  • University of California, Los Angeles

Tags

DTIC Thesaurus Topics

  • Aluminum
  • Aluminum Alloys
  • Boundaries
  • Cartesian Coordinates
  • Civil Engineering
  • Crystals
  • Grain Boundaries
  • Grids
  • Materials
  • Military Research
  • Shear Stresses
  • Single Crystals
  • Strain Hardening
  • Stresses
  • Temperature Gradients
  • Tensile Strain
  • Walls

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Theoretical Analysis.