Elastic behaviour and microstructural characteristics of Nd60Al10Fe20Co10bulk metallic glass investigated by ultrasonic measurement under pressure

Abstract

An ultrasonic pulse–echo method was used to measure the transittime of longitudinal and transverse (10 MHz) elastic waves in a Nd60Al10Fe20Co10bulk metallic glass (BMG). The measurements were carried out under hydrostaticpressure up to 0.5 GPa at room temperature. On the basis of experimentaldata for the sound velocities and density, the elastic moduli and Debyetemperature of the BMG were derived as a function of pressure. Murnaghan’sequation of state is obtained. The normal behaviour of the positive pressuredependence of the ultrasonic velocities was observed for this glass. Moreover, thecompression curve, the elastic constants, and the Debye temperature of theBMG are calculated on the basis of the similarity between their physicalproperties in the glassy state and those in corresponding crystalline state.These results confirm qualitatively the theoretical predictions concerningthe features of the microstructure and interatomic bonding in the Nd60Al10Fe20Co10BMG.