服役温度下热障涂层断裂韧性和残余应力压痕原位表征技术及仪器研制

Thermal barrier coating materials have become important strategic materials in aerospace and defense industries. It is very important to develop advanced in-situ experimental measurement techniques and equipment to improve the coating process parameters and reliability evaluation under service temperatures. Digital image Vickers indentation technique is one of the key technologies of in situ characterize micro-hardness, fracture toughness and residual stress of thermal barrier coating. However, the maximum test temperature of most of Vickers indentation apparatus is less than 1200 centigrade. The load types are not enough to synchronously test fracture toughness and residual stress of high-temperature brittle coatings. The apparatus measurement function is very simple. The present Vickers indentation level is difficult to meet the requirements of high temperature coating test. The price of imported high temperature hardness apparatus is too expensive. On the basis of our previous work, this project pay more attention to develop a multifunction integrated in-situ Vickers indentation technique and experimental apparatus within 1300 centigrade under vacuum environment, and in-situ study macro/micro mechanical performances of thermal barrier coating materials under different service temperatures and vacuum environment. We will propose new interfacial indentation fracture mechanics model, and establish an important date about the relationship of high-temperature micro-hardness, fracture toughness and residual stress of thermal barrier coating. The results are useful for revealing high-temperature macro/micro failure mechanisms of thermal barrier coatings. This work will provide important experimental basis for optimizing the process parameters and improving the reliability of thermal barrier coatings.

热障涂层材料已成为航空航天和国防工业领域的关键材料。发展服役温度下热障涂层性能原位表征技术和装备对于完善涂层制备工艺参数和可靠性评价至关重要。数字图像小负荷维氏压痕技术是实现热障涂层显微硬度、断裂韧性和残余应力快速智能化原位表征的关键技术之一。目前大部分小负荷压痕仪器测试温度低于1200℃，30kgf量程范围内载荷等级少，仪器功能单一，难以满足陶瓷涂层高温断裂韧性和残余应力同步测试要求；进口高温硬度计价格昂贵。本申请项目将充分发挥申请者在热障涂层破坏机理及压痕表征技术方面的工作基础，自主设计和研制1300℃高温真空环境下小负荷高温维氏压痕表征试验装备；发展涂层/基底界面压痕断裂新型力学模型，建立热障涂层显微硬度、断裂韧性、残余应力与试验温度之间的基础数据库，揭示涂层宏微观高温破坏机理，为优化涂层制备工艺参数和提升涂层可靠性提供重要的实验方法。

高温防护涂层已成为航空发动机和高超音速飞行器热端部件的关键材料。发展先进的实验测试技术和实验系统，揭示服役温度下高温涂层力学性能演变特性，总结其失效机理，是获得高可靠性、长寿命涂层的重要基础。项目组发展了适合脆性涂层材料压痕断裂测试的力学模型，并以此为依据，系统改造了传统硬度计，先后设计和研制了高温加载系统、长焦物镜、光学观测系统、滤光系统、载荷加载系统、特殊材质压针等，在国内率先实现了1300 ºC范围内微米尺度下热障涂层压痕断裂原位表征，分别建立了8YSZ、GYbZ涂层显微硬度、断裂韧性、残余应力与测试温度的数据库，进一步揭示了热防护涂层高温失效机理，为快速诊断涂层工艺问题、预测涂层服役寿命提供了重要的试验技术和设备。项目组顺利完成了相关研究任务，取得了预期研究成果，发表12篇SCI，培养16名研究生，获省部级奖励3项。