Metal–non-metal transition in lead–bismuth eutectic

Abstract

Thermodynamic functions and electrical resistivity of Pb-Bi eutectic alloy have been measured over wide ranges of specific volume and pressure in the liquid and gaseous state. The experimental data show a crossover from metallic to insulating behavior in the electrical resistivity of the alloy when its specific volume increases. It is found that in the crossover region the constant volume temperature coefficient of resistivity changes sign from positive to negative and passes through zero at a value of the specific volume which is 2.4 times larger than that in normal state. The second salient feature of the alloy revealed by these experiments is that the isochores plotted in the specific internal energy – pressure plane are straight lines. Based on these experimental data and using an earlier developed approach, an equation of state of the alloy has been constructed whose accuracy is determined mainly by the errors of the measurements. It is shown that this equation of state can be used to obtain direct estimates of the specific volume and pressure at the critical point of the liquid-gas transition as well as the critical volume for the metal-non-metal transition observed in this eutectic. The results indicate that the critical specific volumes for these two transitions are equal, and the metal-non-metal transition can be described by the classical percolation theory.

Equation of State for Bismuth at High Energy Densities

“…Knowledge of the thermodynamic properties of materials in a wide range of highenergy states is required for the analysis of physical phenomena in various processes under intense pulse action on condensed matter [1][2][3]. These processes include high-velocity impact [4][5][6][7], interaction with the material of intense laser radiation [8][9][10][11] or particle flows of high power density [12][13][14], and the electrical explosion of conductors [15][16][17]. For numerical simulations of emerging hydrodynamic flows, it is necessary to know the relationships of the thermodynamic characteristics of the medium in the entire range of realizable states [18][19][20][21][22].…”