Accession Number:

ADA055856

Title:

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

Descriptive Note:

Master's thesis,

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING

Personal Author(s):

Report Date:

1977-09-01

Pagination or Media Count:

68.0

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

Subject Categories:

  • Metallurgy and Metallography
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE