Fatigue Life Improvement Due to Cold Expansion in Al 2650 at 20°C and 150°C

摘要

Cold expansion is employed usually in components to introduce compressive residual stresses exposed only to service conditions near to room temperature. However, there are instances where components are used at elevated temperature. In this paper, fatigue crack growth tests have been carried out at 20°C and 150°C for both cold expanded and non-cold expanded conditions. Crack closure measurements were obtained for different loading conditions and related to observed fatigue crack growth rates. Fatigue crack growth rates in specimens containing cold expanded fastener holes were affected significantly by elevated temperature exposure. Depending on the exposure time and loading conditions the fatigue life improvement was found to be between three and greater than ten for tests at 20PC.