Computations of Ultrasonic Parameters in Alloys

Abstract

The ultrasonic properties like ultrasonic attenuation, sound velocity in the hexagonal alloys have been studied along unique axis at room temperature. The second- and third-order elastic constants (SOEC & TOEC) have been calculated for these alloys using Lennard-Jones potential. The velocities and have minima and maxima, respectively, at 45° with unique axis of the crystal, while increases with the angle from unique axis. The inconsistent behaviour of angle-dependent velocities is associated to the action of second-order elastic constants. Debye average sound velocities of these alloys are increasing with the angle and has maximum at 55° with unique axis at room temperature. Hence, when a sound wave travels at 55° with unique axis of these alloys, then the average sound velocity is found to be maximum. The mechanical and ultrasonic properties of these alloys will be better than pure Zr and Sn due to their high SOEC and ultrasonic velocity and low ultrasonic attenuation. The comparison of calculated ultrasonic parameters with available theoretical/experimental physical parameters gives information about classification of these alloys.

Computational Study of Ultrasonic Parameters of Hexagonal Close-Packed Transition Metals Fe, Co, and Ni

“…The relative magnitudes of C 11 , C 33 , and C 12 are well represented by our theoretical approach, and are in good agreement with the theoretical and experimental results, as shown in Table 1. The obtained values of the SOECs and TOECs are of the same order as those obtained in previous experimental and theoretical studies of other metallic alloys and metals [17,[22][23][24][25]. Hence, our theoretical approach to evaluating the elastic constants seems to be valid for these metals.…”

“…The nature of the angle-dependent velocity curves in the present work is found to be similar to those for heavy rare-earth metals, laves-phase compounds, lanthanide metals, and other hcp wurtzite-structured materials (GaN, AlN, InN) [17,[22][23][24][25][26]. The computed velocities for these three metals are therefore valid.…”

“…• The mechanical and ultrasonic properties of Fe are better than those of Co and Ni because of their low ultrasonic attenuations. • The ultrasonic velocities and thermal relaxation time of these transition metals are greater than those of lanthanide metals (Ti, Zr, and Hf) [25] because of their high elastic constants. The mechanical behaviors of Fe, Co, and Ni will therefore be better than those of the lanthanide metals.…”

Non-destructive characterization of superionic conductor: lithium nitride

“…The order of 'τ' for hexagonal structure is of the order of picoseconds [35]. With reference to some previous work [37], the size dependency of τ for bcc and fcc structured materials follows the equation:…”

Elastic, Mechanical and Thermophysical Properties of Hexagonal Nanostructured Cr$_{2}$N Compound

“…Thus, it is clear that thermal relaxation time for hexagonal Cr2N thin films is mainly affected by the thermal conductivity and thermal energy density. Thermal relaxation time τ is found in order at picoseconds for Cr2N thin film [29,33,34]. Therefore, the evaluated thermal relaxation time explains the nanostructured Cr2N thin films.…”