金属Bi的卸载熔化实验研究

摘要

在火炮上利用金属铋(Bi)直接撞击单晶LiF窗口，开展了金属Bi反向碰撞的冲击加载-卸载实验研究，实验采用激光位移干涉测试系统，获得了金属Bi在11—16 GPa压力范围内完整的卸载粒子速度剖面。实验结果结合特征线方法计算表明，金属Bi经冲击加载进入体心立方相，并在11—16 GPa冲击压力作用下发生了卸载熔化，界面粒子速度剖面的卸载拐点，对应着金属Bi经冲击加载后发生的卸载熔化，而这一结论同Cox的理论计算及一维流体力学程序计算结果基本一致。本文报道的金属Bi卸载波剖面解读技术，对于认识冲击加载下其他相似材料相变具有实用价值。%Reverse-impact experiments are performed on bismuth (Bi) to probe into the release melting from shock pressures in a pressure range of 11–16 GPa. A displacement interferometer system for any reflector (DISAR) is employed to measure the particle velocity history at the impact interface of LiF window with Bi flyer. The obtained experimental data, together with the results from characteristic formulations and one-dimensional hydrodynamic simulations, indicate that bismuth is converted into the body-center-cubic phase under shock loading, and then melted with the releasing of state from the initial shock (Hugoniot). The inflexion on the release wave profiles is attributed to the release melting. The proposed method and extracted results are of importance for developing the phase-change diagnostics and understanding phase-transition behavior of Bi and its analogues.