Accession Number : AD0785249

Title :   Load and Environment Interactions in Fatigue Crack Growth.

Descriptive Note : Technical rept.,

Corporate Author : LEHIGH UNIV BETHLEHEM PA INST OF FRACTURE AND SOLID MECHANICS

Personal Author(s) : Shih,T. T. ; Wei,R. P.

Report Date : MAY 1974

Pagination or Media Count : 26

Abstract : The influences of environment on delay and on fatigue crack growth under programmed loading were examined for a mill annealed Ti-6Al-4V alloy. Test environments included dehumidified argon, air (with 30-60% relative humidity), distilled water, and 3.5% NaCl solution. The effects of load sequence and block size on fatigue under programmed loads were investigated also. Experimental results show that the mildly aggressive environments (atmospheric moisture and distilled water) have little effect on delay. Salt solution, on the other hand, has a significant effect on delay and on crack growth under programmed loading; the effect on delay being dependent on frequency or hold-time. Both load sequence and block size can significantly alter fatigue life under programmed loading. The need for further fundamental understanding of load and environment interactions in fatigue is discussed. (Modified author abstract)

Descriptors :   *Fatigue(Mechanics), *Fracture(Mechanics), *Stress corrosion, *Titanium alloys, Loads(Forces), Aluminum alloys, Vanadium alloys, Salt water, Humidity, Crack propagation

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE