Abstract:

An ultrasonic study of attenuation and sound velocity was carried out in aluminosilicate glasses including annealed samples at 800 and 900 (degrees)C for 10 h as functions of temperature and frequency with the pulse--echo method. The temperature and frequency ranges employed here were 100--300 K and 5--50 MHz. The original sample has the largest attenuation coefficient in the temperature range compared to that of samples annealed. In all samples, the longitudinal and shear-wave velocities decrease linearly with temperature. Young's, shear, and bulk moduli decrease linearly with temperature also. In this temperature range, Lame's parameter, Poisson's ratio, and the velocity anisotropy factor were determined using velocity data. The ultrasonic attenuation coefficient increases linearly with frequency and monotonically with decreasing temperature and is independent of pulse amplitudes. These results imply a linear loss mechanism producing a frequency-independent Q.