Phase diagram of Mo at high pressure and temperature

Ross, M

关键词: FREE ENERGY;    MELTING;    PHASE DIAGRAMS;    POISSON RATIO;    VELOCITY;   

DOI  :  10.2172/945864
RP-ID  :  LLNL-TR-407689
PID  :  OSTI ID: 945864
Others  :  TRN: US200904%%178

学科分类：物理（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

We report values of the Poisson Ratios for shock compressed Mo, calculated from the sound speed measurements, which provide evidence that the 210 GPa ({approx}4100K) transition cannot be a bcc-hcp transition, as originally proposed. Instead, we find the transition is from the bcc to a noncrystalline phase. For pressures above 210 GPa, the Poisson Ratio increases steadily with increasing temperature, approaching the liquid value of 0.5 at 390 GPa({approx}10,000K), suggesting the presence of a noncrystalline solid-liquid mixture. Free energy model calculations were used to show that the low melting slope of Mo, and the phase diagram, can be explained by the presence of local liquid structures. A new phase diagram is proposed for Mo that is constrained by the experimental evidence.