Mechanisms of Fatigue Crack Propagation in Aluminum Alloys.

Abstract

The mechanisms of crack initiation and propagation in fatigue and of crack propagation under a monotonic load were studied in high strength aluminum alloys. Part I is a detailed report on the use of scanning electron microscopy in fatigue crack propagation research. The results are discussed with reference to the theories of fatigue crack propagation. Part II is a documentation of crack initiation and stage I fatigue fracture in aluminum alloys. The existence of non-propagating cracks in aluminum alloys is discussed by comparing the endurance limit and the stress intensity threshold for non-propagating fatigue cracks. Part III REPORTS THE INFLUENCE OF TEMPERATURE AND CYCLIC RATE ON CRACK GROWTH IN 2024 T3 aluminum alloy. Part IV deals with the role of the cold work of the plastic zone at the tip of a crack on the mechanisms of fatigue crack growth rate. Part V is a study of the correlation between the fracture toughnews index K and the tensile properties. This work was undertaken to understand the dependance of the critical stress intensity factor on aging, the workhardening exponent, and plane strain ductility. (Author)

Document Details

Document Type
Technical Report
Publication Date
May 01, 1971
Accession Number
AD0728659

Entities

People

  • Anna M. Wilson
  • K. Erhardt
  • N. J. Grant
  • R. Pelloux

Organizations

  • Massachusetts Institute of Technology

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Alloys
  • Aluminum
  • Aluminum Alloys
  • Crack Propagation
  • Cracks
  • Cyclic Rate
  • Electron Microscopy
  • Intensity
  • Microscopy
  • Scanning Electron Microscopy
  • Stress Intensity Factors
  • Stresses
  • Tensile Properties

Fields of Study

  • Materials science

Readers

  • Business Analytics
  • Materials Science (Mechanical Engineering).

Technology Areas

  • Microelectronics