Effect of Platinum Addition to Coinage Metals on Their Ultrasonic Properties Determination of second- and third-order elastic constants, sound velocity and ultrasonic attenuation

Department of Applied Physics, AMITY School of Engineering and Technology, An Affiliated Institute of Guru Gobind Singh Indraprastha University, Bijwasan, New Delhi-110 061, India; *E-mail: [email protected] Ultrasonic attenuation for the longitudinal and shear waves due to phonon-phonon interaction and due to thermoelastic relaxation mechanisms have been evaluated in bimetallic alloys of the coinage metals (copper, silver or gold) with 1, 2, 3 or 4 at% platinum.The evaluations were carried out along the 〈100〉, 〈111〉 and 〈110〉 crystallographic directions at room temperature. Secondand third-order elastic constants, ultrasonic velocities and thermal relaxation times have also been computed for these alloys. In each case, the addition of platinum to the coinage metal reduces the attenuation, which indicates that bimetallic alloys with a higher platinum content are more ductile and stable and contain fewer defects in their crystal structure than those with a lower platinum content. The predominant mechanism of attenuation of ultrasonic waves is phonon-phonon interaction rather than thermoelastic loss. The results are compared with available theoretical data and experimental measurements for the pure coinage metals.These results, in combination with other well-known physical properties, can be applied to the non-destructive testing of materials for various industrial applications.