Thermal hysteresis of mesoscopic phase transitions in fluid metals: from tantalum to aluminum and gold with their critical points and non-mean-field global diagrams

Abstract

The light soft metal – Al-IIIB (MAl = 27 g .mol-1 ) and the heavy soft metal – Au-IB (MAu =197 g .mol -1) were analyzed within the same predictive model of fluctuation–thermodynamics (FT). The similar extrapolative approach was applied for re-establishing of the global phase diagram and non-mean-field criticality of the refractory heavy and rigid tantalum Ta-VA ( MTa =181g .mol-1) earlier. The revealed then correspondence between the onset point of nano-droplets at atmospheric pressure and the point of instability, observable at much higher pressures by the dynamic (IEX) measurements, found its confirmation for the considered metals as well. It may indicate the universality of the mentioned “dew”- point for any elements and compounds. The mesoscopic nanoscaled time- and length- simultaneous consideration matters especially for all metallic vapors at sub-atmospheric pressures ( P<P0 ) and T<Tb . The FT-predicted critical points of Al{TcAl=6518K ; ρcAl=424.5 kg.m-3 ; PcAl=1369 bar; ZcAl=0.1607} and Au{TcAu=8077 K ; ρcAu=3453 kg.m-3 ; PcAu=2135 bar; ZcAu=0.1814} are consistent with the available low-temperature thermostatic and rapid dynamic experimental data.