Low-cycle dwell-time fatigue in Ti-6242

Ambient-temperature, low-cycle dwell-time and conventional low-cycle fatigu e tests were performed on Ti-6Al-2Sn-4Zr-2Mo-0.1Si (Ti-6242). Specimens wer e solution annealed at various temperatures below the beta transus to contr ol the volume fraction of primary alpha phase and were subsequently shot-pe ened. The influence of the changes in primary alpha phase on the low-cycle dwell-time fatigue life (LCDF) were determined and compared to the conventi onal low-cycle fatigue (LCF) properties of the alloy. A 120-second dwell si gnificantly decreased the number of cycles to failure, although the factor decrease of LCF from a dwell, in general, diminished with decreasing stress . The Increasing primary alpha phase associated with lower solution tempera tures appears to increase susceptibility to low-cycle dwell-time fatigue. I t also appears that the susceptibility to dwell fatigue may be associated w ith ambient-temperature, time-dependent, cyclic (creep) plasticity.