过渡金属高压熔化规律研究

高温高压极端条件下物质特性研究领域当今存在的一个热点问题是，在动、静高压技术测量的过渡金属熔化曲线之间存在着巨大的差异。为了澄清这个问题，本项目拟在前人研究的基础上，以铁、钼两种材料为研究对象，着重在静高压实验中采用国际上新近发展起来的直接测量液相结构技术并排除传压介质对测温结果的可能影响，重新测量其熔化曲线；在动高压实验中则通过提高样品初始温度办法和对Hügoniot声速的精密测量，以期得到从低压到高压的多个压力点上的熔化温度数据，并与静高压的新的测量结果进行比较；最后，再借助第一原理、分子动力学模拟和热力学计算等方法，对前人动、静高压实验测量结果的差异原因提出新认识。

In the research fields of material properties under extreme conditions of high-temperature and high-pressure, a lively controversy exists in the high-pressure melting temperatures of transition metals from diamond anvil cell (DAC) measurements and shock wave (SW) experiments. In this project, based on the previous studies, we will further investigate the high pressure melting properties of iron and molybdenum: firstly, in DAC experiments, with the adoption of recently developed technology of liquid structure measurements and ruling out the probable influence of pressure transmitting media, the DAC melting temperature will be re-examined; secondly, in SW experiments, by the measurements of Hügoniot sound velocity for preheated sample, several credible melting temperature data will be obtained in the comparable pressure range of DAC experiments, and a melting curve will be achieved; finally, through the first principle calculations, molecular dynamics simulations, and thermodynamic analysis, the new perspective for the discrepancy between the predecessors'' SW and DAC measurements will be put forward.