高温高压下UH_(3)结构稳定性及其冲击分解  

Structural Stability and Shock Decomposition of UH3 at High Temperature and High Pressure

作　　者：王玉锋[1] 郝龙[1] 吴凤超 耿华运[1] 李俊[1] WANG Yufeng;HAO Long;WU Fengchao;GENG Huayun;LI Jun(National Key Laboratory of Shock Wave and Detonation Physics,Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621999,Sichuan,China)

机构地区：[1]中国工程物理研究院流体物理研究所冲击波物理与爆轰物理全国重点实验室,四川绵阳621999

出　　处：《高压物理学报》2024年第3期80-89,共10页Chinese Journal of High Pressure Physics

基　　金：冲击波物理与爆轰物理全国重点实验室基金(2023JCJQLB05401,6142A032020010)。

摘　　要：利用统计物理模型构建了UH_(3)晶体及其化学分解产物的状态方程,通过比较Gibbs自由能获得了UH_(3)的高温高压相图,并将其应用于疏松和密实UH_(3)冲击压缩性质研究中。结果表明:等温压缩下,UH_(3)晶体在压力约74.0 GPa时发生化学分解,提高温度有助于化学分解的发生,但压力对UH_(3)化学分解相边界的影响是非单调的;冲击加载下,密实UH_(3)在35~50 GPa压力范围内发生化学分解,并且由于冲击分解伴随着明显的体积塌缩,分解产物的雨贡纽曲线位于等温压缩线下方,曲线位置关系反常;UH_(3)的冲击分解压力随着疏松度的增大而减小,当UH_(3)材料的初始疏松度为1.5时,在化学分解转变压力范围内,UH_(3)的分解产物比UH_(3)晶体更难压缩,表现出类似大疏松度材料在冲击作用下的“反常膨胀”现象。研究结果丰富了对UH_(3)材料动态压缩特性的认识,为锕系金属氢化物的高温高压物理化学性质研究提供了理论参考。Using statistical physical model,the equation of state of UH_(3) crystal and its chemical decomposition products were constructed in this paper.The phase diagram of UH_(3) at high temperature and high pressure was obtained by Gibbs free energy comparison,and the shock compression properties of UH_(3) with different initial densities were investigated.The results show that the chemical decomposition of UH_(3) crystals occurs at about 74.0 GPa under isothermal compression.Increasing the temperature promotes the chemical decomposition,but the influence of pressure on the chemical decomposition of UH_(3) is nonmonotonic.Solid UH_(3) decomposes at 35–50 GPa under shock compression,and the chemical decomposition process is accompanied by obvious volume collapse,therefore,the Hugoniot of UH_(3) decomposition products lies below the isotherm,which is an abnormal phenomenon in comparison with ordinary metals or compounds.Moreover,the decomposition pressure of UH_(3) decreases with the increase of initial porosity.When the initial porosity is about 1.5,the decomposition products of UH_(3) are more difficult to compress than UH_(3) in crystal phase,thus showing a phenomenon similar to the abnormal expansion of large porosity materials under shock compression.These results enrich our understanding of dynamical compression behavior of UH_(3),and can serve as theoretical basis for further research on physical and chemical properties of actinide metal hydrides at high temperature and high pressure.

关 键 词：UH_(3) 氢化物 状态方程 高温高压 结构稳定性 化学分解 

分 类 号：O521.2[理学—高压高温物理]