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Investigation of the effect of vacuum environment on the fatigue and fracture behavior of 7075-T6.Axial-load fatigue-life, fatigue-crack propagation, and fracture-toughness experiments were conducted on sheet specimens made of 7075-T6 aluminum alloy. These experiments were conducted at air pressures ranging from 101 kN/sq m to 7 micronewtons/sq m to determine the effect of air pressure on fatigue behavior. Analysis of the results from the fatigue-life experiments indicated that for a given stress level, the lower the air pressure was the longer the fatigue life. At a pressure of 7 micronewtons/sq m, fatigue lives were 15 to 30 times longer than at 101 kN/sq m. Analysis of the results from the fatigue-crack-growth experiments indicates that at low values of stress-intensity range, the fatigue-crack-growth rates were approximately twice as high at atmospheric pressure as in vacuum. However, at higher values of stress-intensity range, the fatigue-crack-growth rates were nominally the same in vacuum and at atmospheric pressure.
Document ID
19730030962
Document Type
Reprint (Version printed in journal)
Authors
Hudson, C. M. (NASA Langley Research Center Hampton, Va., United States)
Date Acquired
August 7, 2013
Publication Date
December 1, 1972
Subject Category
MATERIALS, METALLIC
Distribution Limits
Public
Copyright
Other