Fatigue Crack Growth in Friction Stir Welded Ti-5111
Abstract
The effects of weld microstructure and weld speed on the fatigue crack growth kinetics of friction stir welded Ti-5111 were investigated. The FSW welds in Ti-5111 consist of very fine recrystallized grains, in contrast to coarse basketweave grains in the base plate. Fatigue crack growth rates are significantly lower and fatigue crack growth thresholds are significantly higher through the weld than those in the base plate. As the weld speed increases, the fatigue crack growth rates are progressively higher and fatigue crack growth thresholds lower through the weld. However, after stress-relief annealing, such differences in fatigue crack growth kinetics among different weld speeds no longer exist. Fatigue crack growth rates through post stress-relieved welds are higher than those in the base metal. The observed fatigue crack growth responses are discussed in terms of differences in crack tip microstructure, compressive residual stresses, crack closure, and crack deflection.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2009
- Accession Number
- ADA536083
Entities
People
- C. R. Feng
- D. W. Moon
- H. N. Jones
- P. S. Pao
- R. W. Fonda
Organizations
- United States Naval Research Laboratory