Fine Subgrain Structure Adjacent to Fatigue Cracks.

Abstract

Deformation microstructures adjacent to fatigue cracks in 2024-T4 and 7075-T6 aluminum, and Ti -6Al -4V alloys have been examined by transmission electron microscopy. The data show that material within 1-2 micrometer of a tensile-mode crack consists of very fine (0.1 micrometer) subgrains in all three materials. The average misorientation between the subgrains is 2-4 degrees. The presence of this substructure, which seems to be independent of initial metallurgical condition, is used to explain the weak dependence of Stage 2 crack growth rates on the initial condition in high stacking fault energy materials. No evidence of precipitate reversion was observed adjacent to the fatigue cracks in 7075-T6 aluminum. (Author)

Document Details

Document Type
Technical Report
Publication Date
Oct 01, 1971
Accession Number
AD0733719

Entities

People

  • G. G. Shaw
  • J. C. Grosskreutz

Organizations

  • MRIGlobal

Tags

DTIC Thesaurus Topics

  • Aluminum
  • Electron Microscopy
  • Electrons
  • Materials
  • Micrometers
  • Microscopy
  • Microstructure
  • Optical Analysis
  • Precipitates
  • Transmission Electron Microscopy

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Powder metallurgy of Titanium alloys.

Technology Areas

  • Microelectronics
  • Microelectronics - Graphene