Behavior of Tin-Bismuth Alloys near Melting Point Found by Measurement of Sound Velocity

The velocities and the attenuation of sound in tin-bismuth alloys of two different chemical compositions, Bi/(Bi+Sn)=57.0 wt% (eutectic) and 66.7 wt% (hypereutectic), have been measured by the pulse transmission method at temperatures below and above the melting point. The frequency of the ultrasonic wave was 1 MHz. The compressional and shear wave velocities in the eutectic alloy just below the melting point (139°) were 2507 m/s and 1130 m/s, respectively, and the compressional wave velocity in liquid just above the melting point were 2040 m/s. By combining the present experimental data with the density and thermal expansivity data of the alloys, the elastic and the anelastic properties of tin-bismuth alloys near the melting temperature were derived, and some discussions were made on the obtained results.