Determination of Threshold Stress Intensity Factors for 7175-T651 Aluminum and Alcoa MA-87 Powdered Aluminum Alloys.

Abstract

Threshold stress intensity factors were obtained for two aluminum alloys: 7175-T651 and Alcoa MA-87, a powdered alloy. Crack growth tests were conducted at room temperature on a Sonntag Universal fatigue testing machine. Edge-cracked bend specimens were used in the tests. Crack length was checked periodically using a Gaertner cathetometer coupled with an auxillary lens placed close to the specimen. Tests were performed at stress ratios of R = 0.1 and R = 0.3. It was found that 7175-T651 had a greater fatigue threshold value than MA-87 when compared at the same stress ratio. It was also found that stress ratio had an effect on the threshold stress intensity factors with increasing stress ratio resulting in a smaller fatigue threshold value. Recommendations have been made for further experimentation with regard to threshold stress intensity factors of powdered aluminum alloys. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1977
Accession Number
ADA055856

Entities

People

  • Donald Roy Holloway

Organizations

  • Air Force Institute of Technology

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Force
  • Aircrafts
  • Alloys
  • Aluminum Alloys
  • Chemical Composition
  • Crack Tips
  • Data Reduction
  • Engineering
  • Fracture (Mechanics)
  • Heat Treatment
  • Literature Surveys
  • Materials
  • Materials Laboratories
  • Mechanical Properties
  • Mechanics
  • Photographs
  • Stress Intensity Factors

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  • Materials Science (Mechanical Engineering).
  • Mathematics or Statistics