Accession Number : AD0871597

Title :   Fatigue Mechanisms and the Development of Fatigue-Resistant Materials.

Descriptive Note : Technical rept. 1 Apr 69-1 Jan 70,

Corporate Author : MIDWEST RESEARCH INST KANSAS CITY MO

Personal Author(s) : Grosskreutz, J. C.

Report Date : MAY 1970

Pagination or Media Count : 43

Abstract : Concentrated research on fatigue mechanisms during the past decade has removed much of the mystery of catastrophic fatigue failure. It is now known that failure is the certain result of the nucleation and growth of highly localized microcracks, and that the rate of accumulation of this type of damage depends on the microstructure of the material as well as certain mechanical properties. In this paper, the accumulated knowledge of fatigue mechanisms is applied to the problem of developing fatigue-resistant materials. Four questions are considered: (1) How can high static yield stresses be maintained under cyclic loading. (2) How can crack initiation be suppressed. (3) How can crack growth rates be reduced. and (4) How do temperature and environment affect the fatigue response of materials. Out of the answers to these questions, guidelines are drown for the development of new materials, with illustrative examples given in which higher fatigue strength has been achieved. Finally, specifications for an ideal fatigue-resistant material are synthesized from the answers provided by fatigue mechanisms knowledge. (Author)

Descriptors :   *FATIGUE(MECHANICS)), (*MATERIALS, CRACKS, CRACK PROPAGATION, STRESSES, DEFECTS(MATERIALS), INHIBITION.

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE