Ultrasonic Methods For The Study Of Stress Cycling Effects In Metals
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Report Number: WADD TR 60-920
Author(s): Truell, Rohn, Chick, Bruce, Anderson, George, Elbaum, Charles, Findley, William
Corporate Author(s): Metals Research Laboratory, Brown University
Laboratory: Materials Central
Date of Publication: 1961-04
Pages: 23
Contract: AF 33(616)-6945
DoD Project: 7360
DoD Task: 73606
Identifier: AD0271067
Abstract:
The use of ultrasonic methods for studying defect formation and its consequences in connection with stress cycling and fatigue of aluminum is the subject of the report. The measurement of changes of ultrasonic attenuation and velocity during stress cycling are show together with the accompanying changes in the metallographic character of the surface sample as determined by acetate replicas and optical methods as well as oxide replicas and electron micrographs. The results of these measurements, especially in the very early stages of stress cycling, support the ideas (advanced in previous reports) that the cycling is accompanied by a dying out of dislocation damping effects, including recovery, as the result of the immobilization of the dislocation oscillation by slip processes together with the increase in scattering caused by the development of defects and strain regions accompanying further slip. It has become quite clear that further advances in this area of work will require the study of high purity aluminum and single crystal aluminum. The creation and improvement of equipment for the automatic recording of attenuation and velocity changes has been a major part of the effort thus far, and a discussion of this equipment appears here.
Provenance: Lockheed Martin Missiles & Fire Control
Author(s): Truell, Rohn, Chick, Bruce, Anderson, George, Elbaum, Charles, Findley, William
Corporate Author(s): Metals Research Laboratory, Brown University
Laboratory: Materials Central
Date of Publication: 1961-04
Pages: 23
Contract: AF 33(616)-6945
DoD Project: 7360
DoD Task: 73606
Identifier: AD0271067
Abstract:
The use of ultrasonic methods for studying defect formation and its consequences in connection with stress cycling and fatigue of aluminum is the subject of the report. The measurement of changes of ultrasonic attenuation and velocity during stress cycling are show together with the accompanying changes in the metallographic character of the surface sample as determined by acetate replicas and optical methods as well as oxide replicas and electron micrographs. The results of these measurements, especially in the very early stages of stress cycling, support the ideas (advanced in previous reports) that the cycling is accompanied by a dying out of dislocation damping effects, including recovery, as the result of the immobilization of the dislocation oscillation by slip processes together with the increase in scattering caused by the development of defects and strain regions accompanying further slip. It has become quite clear that further advances in this area of work will require the study of high purity aluminum and single crystal aluminum. The creation and improvement of equipment for the automatic recording of attenuation and velocity changes has been a major part of the effort thus far, and a discussion of this equipment appears here.
Provenance: Lockheed Martin Missiles & Fire Control