This study examined the split sleeve cold hole expansion (SSCx) capabilities of selected new aluminum-lithium plate and extrusion alloys and the resulting effect on fatigue life. The results showed that all the Al-Li alloys tested in the L-LT plane could be SSCx under severe but realistic conditions without cracking. Specimens taken from the L-ST plane had a higher probability of cracking, but the propensity for cracking was reduced by preferentially orienting the split in the sleeve. The open hole fatigue results showed that all the Al-Li alloys tested obtained significant improvements in fatigue life due to the application of SSCx. The fatigue life of the Al-Li alloys after SSCx was equal to, or in most cases, greater than alloy 2024-T351. Greater improvement in fatigue life was seen as a function of the yield strength due to the higher elastic constraint of the material after SSCx. This resulted in higher levels of compressive residual stresses, which acted to reduce crack propagation and thus increase the fatigue life.
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