FATIGUE CRACK INITIATION AS VIEWED BY SCANNING ELECTRON MICROSCOPY.

Abstract

It is pointed out that high internal stress, commonly regarded as necessary for initiating fracture by unidirectional deformation of a metal, does not seem essential to crack initiation by cyclic deformation of fatigue. An alternative whereby fatigue cracking can be started simply by the geometry of slip movement is generalized. The hypothesis was tested by the recently developed scanning electron-microscope for copper and aluminum specimens subjected to large amplitudes of cyclic strain (torsion), which gives a generalized type of slip movement. This technique in broadly confirming the hypothesis brings out striking forms of initial fatigue damage. (Author)

Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1970
Accession Number
AD0704789

Entities

People

  • William A. Wood

Organizations

  • George Washington University

Tags

DTIC Thesaurus Topics

  • Cracks
  • Electron Microscopes
  • Electron Microscopy
  • Electrons
  • Fatigue Cracking
  • Microscopes
  • Microscopy
  • Scanning
  • Scanning Electron Microscopes
  • Scanning Electron Microscopy

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Theoretical Analysis.

Technology Areas

  • Microelectronics