Composition dependence of thermophysical properties for liquid Zr–V alloys determined at electrostatic levitation state

Abstract

The thermophysical properties of liquid Zr–V alloys covering a whole composition range were systematically measured by an electrostatic levitation technique. A series of maximum undercoolings from 150 to 386 K (0.2 TL) was achieved for 11 different liquid alloys under containerless state and radiative cooling conditions, where Zr83.5V16.5 and Zr20V80 alloys displayed the strongest undercooling ability. The densities of liquid Zr–V alloys were measured over a wide temperature range from overheated to undercooled states, and the results exhibited a linear dependence on temperature for all 11 compositions. Two typical solidification pathways were observed for hypoeutectic alloys. Except for a slowing down of decreasing tendency near a eutectic Zr57V43 alloy, the liquid densities of Zr–V alloys almost decrease linearly with increasing V content. Accordingly, the thermal expansion coefficients of Zr–V alloys were also derived from containerless measurements, and they showed an increasing tendency with V content. Since thermal radiative dominated the heat transfer process, the ratio of isobaric specific heat to hemispherical emissivity was directly deduced from the thermal balance equation, leading to a quadratic relationship with temperature. It was found that the increase of V content enhanced the ability of radiative heat dissipation below 16.5 at. % V content.