Third-order elastic constants, pressure derivatives of the second-order elastic constants and anderson-grüneisen parameter δ of rhenium

Abstract

Recently the second-order elastic (SEE) constants of single-crystal Rhenium and their pressure derivatives have been measured at 25 ~ by -~iA~aH~AN~ et al. (1). Rhenium is a h.c.p, crystal with c/a-ratio equal to 1.615 at 25 ~ which is slightly less than the ideal value. The object of the present paper is to evaluate the third-order elastic (TOE) constants of Rhenium which have nearly the ideal axial ratio value on the basis of a nearest-neighbour central interact ion model. These TOE constants are then used to evaluate the pressure derivatives of the SOE constants of Rhenimn which are compared with the experimental values (1). The Anderson-Griineisen parameter 6 (~,a) is also evaluated for Rhenium from its TOE data. SRINIVASAN and RA~JI RAo (~) worked out the thermal expansion of an ideal h.c.p. latt ice with a nearest-neighbour central interact ion potential of the type