6533b835fe1ef96bd129ea52
RESEARCH PRODUCT
X-ray diffraction measurements of Mo melting to 119 GPa and the high pressure phase diagram
Reinhard BoehlerMohamed MezouarDaniel ErrandoneaMarvin RossDavid Santamaría-pérezGoutam Dev Mukherjeesubject
MolybdenumShock wave effectsDiffractionMaterials scienceShock (fluid dynamics)General Physics and Astronomychemistry.chemical_elementThermodynamicsMeltingCrystal structureAcoustic wave velocity ; High-pressure effects ; Melting ; Molybdenum ; Phase diagrams ; Shock wave effects ; X-ray diffractionX-ray diffractionUNESCO::FÍSICA::Química físicaHigh-pressure effectsCrystallographychemistryAcoustic wave velocityMolybdenumSpeed of soundHigh pressureX-ray crystallographyPhase diagramsPhysical and Theoretical Chemistry:FÍSICA::Química física [UNESCO]Phase diagramdescription
In this paper, we report angle-dispersive X-ray diffraction data of molybdenum melting, measured in a double-sided laser-heated diamond-anvil cell up to a pressure of 119 GPa and temperatures up to 3400 K. The new melting temperatures are in excellent agreement with earlier measurements up to 90 GPa that relied on optical observations of melting and in strong contrast to most theoretical estimates. The X-ray measurements show that the solid melts from the bcc structure throughout the reported pressure range and provide no evidence for a high temperature transition from bcc to a close-packed structure, or to any other crystalline structure. This observation contradicts earlier interpretations of shock data arguing for such a transition. Instead, the values for the Poisson ratios of shock compressed Mo, obtained from the sound speed measurements, and the present X-ray evidence of loss of long-range order suggest that the 210 GPa ( ∼ 4100 K) transition in the shock experiment is from the bcc structure to a new, highly viscous, structured melt. Daniel.Errandonea@uv.es
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2009-01-01 |