Temperature-dependent ultrasonic attenuation due to phonon–phonon (p–p)

interaction, thermoelastic loss and dislocation damping due to screw and edge

dislocations were investigated in fcc (NaCl B1 type) structured group-IVb and Vb

monocarbides (transition metal carbides, namely TiC, ZrC, HfC, VC, NbC and

TaC) at 50 to 500K, along the three crystallographic directions of propagation,

namely [100], [110] and [111] for longitudinal and shear modes of propagation.

The second-and third-order elastic moduli obtained at different temperatures using

the electrostatic and Born repulsive potentials and taking interactions up to nextnearest

neighbours, were used to obtain Gruneisen numbers, acoustic coupling

constants and their ratios along different directions of propagation and polarization

for longitudinal and shear modes of wave propagation. The temperature variation

of the phonon relaxation time exhibited exponential decay.

Ultrasonic Attenuation Due to Phonon–Phonon Interaction, Thermoelastic Loss

and Dislocation Damping in Transition Metal Carbides. R.K.Singh, R.P.Singh,

M.P.Singh, P.C.Srivastava: Journal of Physics - Condensed Matter, 2008, 20[34],

345227