Accession Number : AD0808447

Title :   ON IMPROVEMENT OF FATIGUE LIFE BY DISPERSAL OF CYCLIC STRAIN.

Descriptive Note : Technical rept.,

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

Personal Author(s) : Nine, H. D. ; Wood, W. A.

Report Date : JUL 1966

Pagination or Media Count : 24

Abstract : Tests are made of a hypothesis that fatigue occurs because cyclic strain concentrates in preferred zones instead of spreading uniformly through the microstructure of a metal as unidirectional strain does. Attempts are made to utilize the hypothesis and improve fatigue lives of copper polycrystals and single crystals by using prior cycling at elevated temperatures to enforce dispersal of strain. In polycrystals the procedure cannot be applied successfully because of concentrations of strain at grain boundaries but it can in single crystals. (Author)

Descriptors :   *NOTCH SENSITIVITY), (*FATIGUE(MECHANICS), (*COPPER, FATIGUE(MECHANICS)), HEAT, DISLOCATIONS, TEMPERATURE, SINGLE CRYSTALS, DEFORMATION, CRYSTALS, STRAIN(MECHANICS).

Subject Categories : Metallurgy and Metallography
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE