HIGH-TEMPERATURE FATIGUE IN CONTROLLED ENVIRONMENTS
Abstract
The effect of environment on the high-temperature fatigue properties of nickel, Type 316 stainless steel, and Inconel X was investigated by comparing the fatigue life in air to that in vacuum at 1500 F. Sheet-metal specimens of these materials were cycled in reverse bending at their resonant frequency by means of equipment developed to perform high-temperature fatigue tests in controlled environments. The effect of environment on fatigue properties is similar for all three materials. At high strains fatigue lives are superior in vacuum; with decreasing strain the vacuum and air curves converge. These results can be explained by a mechanism previously proposed to interpret similar findings in creep. This mechanism involves the simultaneous operation of two competing processes: the surface adsorption of gaseous impurities lowers the surface energy and facilitates crack propagation, while oxidation provides a strengthening tendency. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 08, 1961
- Accession Number
- AD0265419
Entities
People
- G. J. Danek Jr.
- H. H. Smith
- M. R. Achter
Organizations
- United States Naval Research Laboratory