LOW-FREQUENCY DAMPING AND ULTRASONIC-ATTENUATION IN TI3SN-BASED ALLOYS

Studies of high-temperature alloys in the Ti-Sn system based on the in termetallic compound Ti3Sn have identified alloys that damp strongly b oth at low frequencies (0.1 to 10 Hz) and high frequencies (5 to 20 MH z). The low frequency damping behavior shows loss factors as high as 0 .04 at room temperature and Young's moduli that rise with temperature from 40-degrees-C to 100-degrees-C for two alloys. Although the basic mechanism or mechanisms of energy dissipation are presently unknown, t he alloys are notable for unusual shapes of microhardness indentations . The deformations imply that large reversible strains can occur at te mperatures from 23-degrees-C to 1150-degrees-C.