This paper presents the results of a detailed study of the micromechanisms of room-temperature fatigue damage in a metastable beta Ti-15V-3Cr-3Al-3Sn composite reinforced with SiC (SCS-6) fibers. Mechanistically based fracture mechanics/acoustic emission models are then applied to the prediction of the total number of AE counts to failure. The predicted number of AE counts to failure are in good agreement with the experimental measured number of counts to failure. The implications of the results are also discussed for potential applications of acoustic emission techniques in prognostic and diagnostic non-destructive evaluation devices.