Effect of High Pressure on the Compressibilities of Five Alloys

Abstract

The effect of high pressure has been measured on a series of alloys, including Fe plus 8 at. % Si, which has a (disordered) bcc structure, Fe3Al and Fe3Si, which have an ordered bcc structure, and FeAl and AgMg, which have the CsCl structure. The compressibilities of all the alloys except Fe3Si decrease with increasing pressure and lie between those of the pure components. For Fe3Si the compressibility increases slightly with increasing pressure and is less than that either of pure iron or pure silicon.

The dependences of the elastic stiffness moduli and the Poisson ratio of natural iron pyrites FeS2upon pressure and temperature

“…The isothermal hydrostatic pressure derivative (dB/aP);=o of the bulk modulus has been obtained as 7.14 using the method described in Yogurtp et a1 (1985). The compression of FeS2 determined from the Murnaghan equation ( 6) is in reasonable agreement (figure 5 ) within experimental error with that obtained by Clendenen and Drickamer (1966) from the effect of hydrostatic pressure on the lattice parameter. Hence the bulk modulus and its hydrostatic pressure derivative determined from the ultrasonic measurements are in accord with the lattice parameter dependence upon pressure.…”

“…Similarly the specific heat C,(T) at constant volume has been evaluated from the measurements of Ogawa (1976); C, at 295 K is 61.948 J mol". Using the bulk modulus data obtained here, we find yth at 295 K Clendenen and Drickamer (1966) from the effect of hydrostatic pressure on the lattice parameter (which has not been corrected for revision of pressure scale); the lower curve is that obtained here using the Murnaghan (1944) equation of state (6) from the bulk modulus and its hydrostatic pressure derivative determined from the ultrasonic experiments. is 1.54, which is in reasonable agreement with, and updating, the value of 1.8 quoted by Vaughan and Drickamer (1967).…”

“…The compression V(P)/V, for FeS, at room temperature. The upper curve is that determined byClendenen and Drickamer (1966) from the effect of hydrostatic pressure on the lattice parameter (which has not been corrected for revision of pressure scale); the lower curve is that obtained here using theMurnaghan (1944) equation of state (6) from the bulk modulus and its hydrostatic pressure derivative determined from the ultrasonic experiments.…”