Accession Number:

AD0610562

Title:

SOME DIRECT OBSERVATIONS OF CUMULATIVE FATIGUE DAMAGE IN METALS.

Descriptive Note:

Technical rept.

Corporate Author:

COLUMBIA UNIV NEW YORK INST FOR THE STUDY OF FATIGUE AND RELIABILITY

Personal Author(s):

• WOOD,W. A.
• Reimann,W. H.

Report Date:

1964-10-01

Pagination or Media Count:

28.0

Abstract:

Metallographic techniques which have been used in previous work to study how fatigue damage develops in fatigue specimens subjected to cyclic strain at constant amplitude are extended to study of damage produced when cyclic strain is commenced in one range of amplitudes and continued in another. Reactions particularly studied have been those between what have been termed the H or large-amplitude range and the F or smallamplitude range as found in Fcc metal. It is shown how the type of damage produced by combination of H and F amplitudes differs from that which would be produced by either amplitude alone and depends upon the order in which they are applied. Damage is especially drastic if H cycles follow a sequence of F cycles which have established slip-zone fissures and on the basis of the observations suggestions are made on how this particular consequence may be avoided. Author

Descriptors:

• *FATIGUE(MECHANICS)
• METALS
• FATIGUE(MECHANICS)
• STRAIN(MECHANICS)
• CRYSTAL STRUCTURE
• CRYSTAL DEFECTS
• BRASS
• COPPER
• DEFORMATION
• GRAIN STRUCTURES(METALLURGY)
• MICROSTRUCTURE
• FRACTURE(MECHANICS)
• METALLOGRAPHY

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE