Cascading crystallographic transitions α → ω → β → β’→ β" and melting curve of elemental zirconium

Precise fitting of the experimental data analyzed separately for each identified crystallographic phase (α, ω, β, β′and β") yield different bulk moduli Bo and Bo’ zero pressure volumes (Vo) than those claimed in literature. Special attention is given to bcc phases indicating cascading transitions β → β’→ β” associated with volume collapse. The present analysis reveals existence a bcc-β′ which reported here first time. It shown that order collapse at ~58 GPa (β β′) followed by moderate transition bcc-β” phase. β′ stable up 110 GPa. Above dominant ~220 derived bcc-β" are confirmed Lindemann-Gilvarry criterion as simultaneously fit both P–V EOS P-T melting points (combined approach). calculated curve elemental Zr, taking into account thermal Poth shift elevated Tmo’ Poth, very good permitting safe extrapolation high pressures temperatures. In addition, combined approach lead direct determination Grüneisen parameter γo, needed applying approximated formula. DFT (QMD) simulations non-hydrostatic thermodynamic formalism solid mediums mismatch data.