Establishing a mechanistic understanding of dynamic fracture is critical for the design of efficient and safe structural materials. Transformation toughening describes the process by which a crystal structure change can reduce the crack-driving force. The understanding of the dynamic behavior of transformation-toughened materials is limited. To clarify the relationship between crystal structure transformations and toughening during a dynamic loading, we carried out a time-resolved x-ray diffraction study of yttria-stabilized tetragonal zirconia polycrystal under shock loading. The results show that the ambient tetragonal crystal structure is maintained on loading and phase transformation to the monoclinic phase occurs only after the onset of dynamic fracture, indicating that the transformation toughening is associated with dynamic fracture caused by wave interactions. This study not only revealed the reason for the high spall strength of zirconia ceramics but also demonstrated the great potential for time-resolved x-ray diffraction method to study fracture dynamics.

中文翻译：

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氧化锆陶瓷动态断裂过程中相变韧化的可视化

建立对动态断裂的力学理解对于设计高效和安全的结构材料至关重要。相变增韧描述了晶体结构变化可以降低裂纹驱动力的过程。对相变增韧材料的动态行为的理解是有限的。为了阐明动态加载过程中晶体结构转变与增韧之间的关系，我们对冲击加载下氧化钇稳定的四方氧化锆多晶进行了时间分辨 X 射线衍射研究。结果表明，加载时保持周围的四方晶体结构，仅在动态断裂开始后才发生向单斜相的相变，表明转变增韧与波相互作用引起的动态断裂有关。这项研究不仅揭示了氧化锆陶瓷具有高剥落强度的原因，而且证明了时间分辨 X 射线衍射方法在研究断裂动力学方面的巨大潜力。