ZrB2基超高温陶瓷材料高温力学行为及本构模型研究

Ultra-High Temperature Ceramic (UHTC) is one of the most preferred materials for key thermal structures of hypersonic vehicles under sever aerodynamic thermal environment. Its mechanical behavior is very sensitive to temperature, and its engineering application potential is limited due to insufficient knowledge of its temperature dependent linear-nonlinear-strong plastic transformation characteristics. This program is focused on the ZrB2-based UHTC and aim at breakthrough in high temperature strain field measurement and in-situ dynamic image acquisition of damage in the first place. Then we proceed with experiment studies on UHTC high temperature mechanical properties, followed by in-depth analysis of the strength’s temperature dependence with quantum function based model, in order to establish temperature sensitive characterization and prediction model of UHTC. Next, with inversion and identification method using combination of experiments and simulation, this program seeks to build a high temperature, multi-parameter constitutive model of linear-nonlinear-strong plastic characteristics of UHTC. Based on these researches, this program will lay a foundation for general and reliable characterization and evaluation methods of UTHC, and improve domestic design technology level of UHTC hot structure.

超高温陶瓷材料作为未来高超声速飞行器防热系统关键热端部件的首选材料之一，主要服役于极端气动热环境，其力学行为对温度非常敏感。现阶段对超高温陶瓷在不同温度下表现出的弹性-非线性-强塑性转变特征尚缺乏科学的表征模型，严重影响其工程应用潜力。本项目以ZrB2基超高温陶瓷材料为研究对象，突破高温应变场、破坏模式原位动态测试技术；开展该材料高温力学性能实验研究，深入分析其强度随温度变化的内在本质，建立含有量子函数的高温强度模型，实现温度敏感的强度评价与预报，从微观层面揭示其高温失效机理；基于实验与模拟结合的反演辨识方法，构建超高温陶瓷材料弹性-非线性-强塑性多参量高温本构模型，为建立全面可靠的超高温陶瓷材料力学行为表征与评价方法奠定理论基础，提高我国超高温陶瓷结构的设计与分析水平。

ZrB2基超高温陶瓷材料是下一代高机动长航时可重复使用高超声速飞行器关键热端部件的候选材料之一，其力学行为对温度的敏感性是决定其结构使役性能的关键。本项目突破了高温应力、应变和破坏模式原位动态测试关键技术，实现了重要力学参量同步获取。获得了2000℃以内材料高温力学性能随温度的变化规律，其中1600℃以下为弹性、1800℃出现了典型的非线性表现出现塑性变形、2000℃出现严重的塑形变形，结合在线测试参量建立了高温强度模型，并揭示了陶瓷高温失效机理。在此基础之上，初步构建了反演辨识策略与数据匹配方法，针对陶瓷材料高温力学性能对温度表现出的弹塑性转变，修正并建立了超高温陶瓷材料弹性-非线性-强塑性多参量高温本构模型，计算结果与实验相吻合。本项目的实验方法和模型为建立全面可靠的超高温陶瓷材料力学行为表征与评价方法奠定理论基础，提高我国超高温陶瓷结构的设计与分析水平。