纳秒尺度金属熔化相变数值模拟及实验验证

Transformation kinetics of metal and experimental measurement at nanosecond order

本文基于非均匀成核相变动力学理论和热传导方程研究了在极快速升温(1012K/s)条件下金属达到过热状态后发生熔化相变时,通过金属/光学窗口界面温度的演化历史研究了金属内部温度的变化情况.分析结果表明,当金属内部无熔化发生时,界面温度将很快达到平衡,此变化满足理想接触界面模型;而当金属内部有熔化发生时,界面温度受熔化速率的影响不能立即达到平衡而是经历了一个下降的弛豫过程.计算结果与实验观测结果进行比较后发现两者符合得较好,由此可以获得金属在高压下的熔化速率,熔化温度等相关信息.本文的研究为金属在高压下的熔化线和熔化速率的研究及测量提供了一种新的理论方法和实验判据.

This paper reports the temperature relaxation process at melting iron /sapphire interface under shock compression,and interpretes the phenomenon basing on transformation kinetics and heat conduction equation. Analysis shows that if iron keeps melting,the history of interface temperature is affected by the melting speed. The interface temperature undergoes a slow cooling process when the melting speed of iron is finite,which is different from the result of previous researches. Simulation signal can be made accord ant with the experimental signal by adjusting some parameters. It was found that the melting temperature and melting speed of iron at high pressure can be dctermined by researching the relaxation process. So,this paper shows a new theoretical method and its experimental verification.