Melting of tantalum at high pressure determined by angle dispersive x-ray diffraction in a double-sided laser-heated diamond-anvil cell

Abstract

The high pressure and high temperature phase diagram of Ta has been studied in a laser-heated diamond-anvil cell (DAC) using x-ray diffraction measurements up to 52 GPa and 3800 K. The melting was observed at nine different pressures, being the melting temperature in good agreement with previous laser-heated DAC experiments, but in contradiction with several theoretical calculations and previous piston-cylinder apparatus experiments. A small slope for the melting curve of Ta is estimated (dTm/dP = 24 K/GPa at 1 bar) and a possible explanation for this behaviour is given. Finally, a P-V-T equation of states is obtained, being the temperature dependence of the thermal expansion coefficient and the bulk modulus estimated.

arXiv comment31 pages, 8 figures, to appear in J.Phys.:Cond.Matter

References in corpus (3)

• Iron under Earth's core conditions: Liquid-state thermodynamics and high-pressure melting curve
• High Pressure Thermoelasticity of Body-centered Cubic Tantalum
• Analysis of Dislocation Mechanism for Melting of Elements: Pressure Dependence

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