低强度陶瓷热冲击断裂抗性和损伤抗性的优化匹配

The research of thermal shock resistance is of great scientific significance for the design and application of structural ceramics. Scholars have been keen on solving this complicated issue for years. Thermal shock behavior is a comprehensive performance of the thermal shock fracture resistance (TFR) and damage resistance (TDR) of materials. Therefore, the designs which only focus on TFR and ignore the TDR as well as the conflict between them two have certain blindness. Especially for the low strength ceramics, the material performance decays with the load changing continuously, thus TDR study on the safe use of these components is essential. Alumina, a based structural material, was used here to be introduced pores to tailor material physical properties, to determine the essential connection among the TFR/TDR, material microstructure and properties and to reconcile the contradictory of the material requirements of TFR and TDR on some physical properties. The ceramics of which TFR and TDR match well are obtained, finally. Looking forward to this research could reveal the essence of thermal shock damage by the multi-scale characterization of thermal shock damage mode of ceramics and examination of its influence on the key performance of the materials, provide a scientific method for the research on thermal shock damage of ceramic materials, and a new idea for the thermal shock performance optimization of ceramic materials.

抗热冲击性能研究对陶瓷的设计和应用具有重要科学意义，是学者们关注的热点与难点。热冲击行为是材料热冲击断裂抗性（thermal shock fracture resistance TFR）和损伤抗性（thermal shock damage resistance TDR）的综合体现，只关注TFR而忽视TDR以及二者间冲突的材料设计理念具有一定的盲目性，特别是对低强度陶瓷而言，性能的衰减随着载荷的增加是连续变化的，TDR研究对于材料的安全使用至关重要。本研究以氧化铝这一基础结构陶瓷为例，引入孔隙以调控材料的物理性质，确定TFR和TDR与微观结构和性质的本质联系，调和TFR和TDR对材料某些物理性质要求相反的矛盾，获得TFR和TDR匹配良好的陶瓷，多尺度表征材料在热冲击下的损伤模式及其对材料关键性能的影响，揭示热冲击破坏的本质。为陶瓷材料的热冲击损伤研究和热冲击性能优化提供科学方法和新的思路。

陶瓷材料由于具有优良的综合性能广泛应用于高温环境，但是在实际服役过程中不可避免的会经历温度的骤然变化（热冲击），过于剧烈的热冲击载荷往往会造成陶瓷构件的破裂和损伤，威胁着整个工程的安全，抗热冲击性能研究对陶瓷材料的设计和应用具有重要科学意义。材料的热冲击行为是其热冲击断裂抗性TFR和损伤抗性TDR的综合体现。本项目创新性地将孔隙引入，调控材料的物理性能以调和TFR和TDR对材料某些物理性能要求相反的矛盾。在考虑材料热冲击临界温差和某一温度下的残余强度保持率的同时，还细致研究了材料在这一过程的强度衰减速率K，阐明了这一关键参数和材料性能之间的关系；确定了在不同微观孔结构下TFR和TDR与孔特性和材料性能的关联规律，重点研究了孔隙组成对材料热冲击性能的影响，给出了具体情况下TFR和TDR匹配良好的多孔陶瓷的设计要求；搭建了热冲击裂纹实时观测平台，采取简化试样热冲击载荷边界条件、改变热冲击试样尺寸等方式，多维度表征材料在热冲击下的损伤模式及其对材料关键性能的影响。为陶瓷材料的热冲击损伤研究和热冲击性能优化提供了新的科学方法和思路。