金属陶瓷表面热-力耦合损伤机理的多尺度研究

金属陶瓷在苛刻环境下服役时，由温升、磨损等引起的热-力耦合损伤是其失效的重要原因，需要从原子、分子层次和热、动力学基础理论角度阐释其多因素耦合表面损伤机制。本项目拟采用粉末冶金方法制备WC-Co、TiC-Fe以及添加元素（Fe、Al、Y）改性的金属陶瓷材料，并对其在高温、高应力苛刻条件下的宏观磨损行为以及微观和原子尺度磨损机理进行系统性研究：基于关键实验构建宏观磨损图，确定硬质相和粘结相的失效条件；利用实验结合相图热力学计算，探索磨损过程中金属陶瓷及表面氧化膜、摩擦膜的微观相变规律；基于第一性原理计算，研究材料表面晶体结构与力学性能变化以及原子吸附与扩散行为。本项目的完成，将从苛刻工况下热-力耦合损伤的角度出发，为金属陶瓷的进一步改性提供实验依据，同时为新一代环境适应型金属陶瓷材料的工程化应用提供理论基础。

The catastrophic failures of ceramic-metal composites under severe working conditions normally stem from the thermo-mechanical coupled wear damages; thus, understanding the underlying wear mechanisms at molecular and atomistic levels as well as from the perspectives of thermodynamics and kinetics is of significance. This project aims at designing novel WC-Co and TiC-Fe composites with Fe, Al, Y elements additions, and investigating their wear behavior under extreme conditions at different scales. The loading conditions at which the ceramic and binder phases fail will be determined by constructing macroscopic wear maps; the phase transitions that may occur in composites’ structure, surface oxide layers and tribolayers will be studied using microscopic and spectroscopic analyses combining with the CALPHAD (CALculation of PHAse Diagram) method; in addition to the changes of crystal structures and mechanical properties, the behaviors of atomic adsorption and adatom diffusion will be explored using first principles calculation. The proposed research is expected to provide bases, from the perspective of thermo-mechanical coupled damage under extreme conditions, for both the further modification and the future industrial application of novel environmentally adaptable ceramic-metal composites.