Damping capacity of laminates composed of layers of titanium alloy and titanium alloy MMC

AbstractThe damping capacity has been determined for symmetrical 3 and 5 layer laminates composed of diffusion bonded IMI 834 Ti alloy and Ti-6AI-4V alloy/Sigma fibre MMC sheets. The MMC represented 50 volume per cent of the laminates and was present as a single layer or two thinner layers within the cross-section (C type laminate) or as two surface layers of the laminate (S type laminate). Control test pieces consisted of 100% IMI 834 and 100% MMC. The damping capacity Q−1 was obtained by the freely vibrating test piece method or by the resonant frequency method. The results show that the damping capacity cannot be predicted by the rule of mixtures. The S type laminate had a Q−1 value 2.3 times greater than the IMI 834 alloy, compared with the 100%MMC test piece which was 2.7 times greater. Ti alloy composite laminates allow cost effective utilisation of the MMC.