耐火材料裂纹端部场与热震断裂能耗散机制研究

由于耐火材料抗热震问题的复杂性，加之缺少获取热震裂纹尖端局域应力场信息的有效手段，宏观力学信息与微观结构的关系尚不明确，在热震损毁的物理本质研究方面，迄今仍未建立起较为完善的理论。本课题针对耐火材料裂纹局域应力场与热震断裂能耗散机制开展研究工作，拟采用SERS成像技术对裂纹扩展过程区与裂尖塑性区进行原位表征，研究耐火材料微结构对裂纹尖端应力场的影响，深入研究热震裂纹局域应力分布与裂纹扩展/闭合行为，探索颗粒相增韧界面对热震断裂能耗散过程影响的内在物理机制。通过弹塑性模型对裂尖塑性区应力/应变行为模拟分析，揭示裂纹过程区、裂尖塑性区和应变幅等因素对耐火材料热震裂纹扩展的影响机理，阐明热震裂纹扩展过程中裂纹尖端应力行为对材料抗热震性能的影响规律，完善复相耐火材料体系热震损伤理论，为提高耐火材料抗热震稳定性提供理论依据。

Due to the intrinsic complexity of thermal shock and the absence of access to the refractory thermal shock crack tip stress field, the macro-mechanical information and micro-structure relationship is not clear. And the fundamental mechanism of thermal shock damage has not yet been established. This project is focused on the local stress field near the crack front and thermal shock fracture energy dissipation mechanism of refractories. The in situ characterization of the fracture process zone stress and the crack-tip plastic zone of refractories will be carried out via SERS Mapping technology to study the effects of refractory micro-structure on the crack-tip stress field. Furthermore, the study will be extended to the thermal shock crack local stress distribution and crack propagating/closing behavior, to explore the impact of the particle phase toughening interface on the thermal shock fracture energy dissipation mechanism. The numerical simulation analysis of the crack tip plastic zone stress/strain behavior will be carried out by using elastic-plastic model to reveal the mechanism of factors influencing the refractory thermal shock crack propagation, such as the crack process zone, crack tip plastic zone and strain amplitude, and to elaborate the impact of the crack tip stress behavior on the effects of material thermal shock resistance in the thermal shock crack propagation process. The objective of this project is to enrich the shock damage theory of refractory, and provide a theoretical basis to practical route for improving the thermal shock resistance of refractory.