The phase transitions of ferroelectric ceramics under dynamic compressions are of importance for materials and applications design. However, there are very few effective methods for describing the shock-induced phase transition process in ferroelectric ceramics, due to the tiny structural volume change during compression. Here the phase transition behaviors of KNb⁢O3 ceramics under compression are studied by measuring electrical responses. A model describing the phase variation in ferroelectric ceramics under uniaxial compressions with respect to pressures has been established, which may provide a reference for studying dynamic phase transitions in ferroelectrics under shock waves. Unlike hydrostatic high-pressure processes, the shock-induced phase transition initiates at relatively low pressures and increases progressively as the pressure rises. Random orientations of the grains in ceramics lead to different pressure conditions of each grain, which is responsible for the gradual phase transition processes. The proportion of phase transitions in three-dimensional space can be visualized using ab initio density functional theory. These findings have significant implications for material design and optimization.

中文翻译：

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冲击压缩作用下铌酸钾的动态相变建模


铁电陶瓷在动态压缩下的相变对于材料和应用设计具有重要意义。然而，由于压缩过程中结构体积变化很小，因此很少有有效的方法来描述铁电陶瓷中冲击诱导的相变过程。在这里，通过测量电响应来研究 KNbO3 陶瓷在压缩下的相变行为。建立了描述铁电陶瓷在单轴压缩下随压力变化的模型，这可能为研究铁电体在冲击波下的动态相变提供参考。与静水压高压过程不同，冲击诱导的相变在相对较低的压力下开始，并随着压力的升高而逐渐增加。陶瓷中晶粒的随机取向导致每个晶粒的压力条件不同，这是逐渐相变过程的原因。三维空间中相变的比例可以使用 ab initio 密度泛函理论进行可视化。这些发现对材料设计和优化具有重要意义。