Fatigue Crack Growth Rates of High-Magnesium Aluminum-Magnesium Alloys as Influenced by Solution Treatment Time and Alloy Content.

Abstract

Test equipment was fabricated and fatigue crack propagation data were obtained for aluminum alloy 7075-T6 and for thermomechanically processed A1-10.2 Wt Pct Mg-0.52 Wt Pct Mn, and A1-8.14 Wt Pct Mg-0.40 Wt Pct Cu alloys. The crack growth data and fractographic information obtained for the 7075-T6 alloy were consistent with data in the literature. The manganese containing alloy was solution treated for nine and twenty-five hour periods. Observed was a decrease in the fatigue crack growth resistance for the longer solutioning time, which appears to be due to the formation and coarsening of Mn A16 precipitates which fail to dissolve in solution treatment during thermomechanical processing. The copper containing alloy exhibited better crack growth resistance than the 7075-T6 alloy. This alloy has a more diffuse cell structure, relatively little precipitated Mg5A18, and no constituent particles associated with cell of grain boundaries. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1983
Accession Number
ADA132928

Entities

People

  • Kurt D. Oberhofer

Organizations

  • Naval Postgraduate School

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Alloys
  • Aluminum Alloys
  • Electron Microscopy
  • Engineering
  • Grain Boundaries
  • Magnesium Alloys
  • Materials
  • Mechanical Engineering
  • Mechanical Properties
  • Mechanical Working
  • Mechanics
  • Resistance
  • Scanning Electron Microscopy
  • Tensile Properties
  • Tensile Strength
  • Tensile Testing
  • Transmission Electron Microscopy

Fields of Study

  • Materials science

Readers

  • Materials Science and Engineering.
  • Metallurgy
  • Structural Health Monitoring of Composite Structures.