本项目首次开展对表面纳米化TC4表面完整性的表征与评价，并针对表面完整性对疲劳性能的影响机理这一科学问题深入开展研究。首先，采用超声喷丸技术（USSP）制备表面纳米化TC4，建立合理的表征表面纳米化金属材料表面完整性的评价参数和表征方法。其次，改变USSP工艺，对USSP工艺参数对表面完整性的影响进行分析，并研究其影响趋势和规律。再次，测试具有不同表面完整性的表面纳米化TC4的弯曲疲劳性能，探讨表面完整性对疲劳极限、疲劳裂纹萌生与扩展行为的影响规律。然后，对表面完整性对表面纳米化TC4疲劳性能的影响进行数值模拟。最后，将实验研究和数值模拟相结合，深入探究表面完整性对疲劳性能的影响机理，为通过优化表面完整性提高材料抗疲劳性提供理论基础。本研究有利于深化对表面纳米化金属材料疲劳机理的认识、全面揭示表面纳米化金属材料的变形行为和变形机理，对推动表面纳米化金属材料的开发、设计、应用具有重要意义。

The surface integrity of suface nanocrystallined TC4 will be characterized and evaluated by the first time in this project, and the mechanism of effect of the surface integrity on its fatigue property will be studied deeply.1) Surface nanocrystallined TC4 will be fabricated by USSP,and the proper evaluation parameters and characterization method will be built up.2) The effect of USSP parameters on the surface integrity will be studied by varying USSP parameters,and how it effects will be analysed.3) The bending fatigue property of suface nanocrystallined TC4 with different surface integrities will be tested,and the the effect of the surface integrity on fatigue limit,the initiation and propogation of fatigue crack will be studied.4) The simulation of this effect will also be investigated. 5) The mechanism of effect of surface integrity on its fatigue property will be studied deeply by combining the experiment with the simulation, and the theory basis will be provied for the design by which the fatigue property will be improved through optimizing the surface integrity.This study will help better understand the fatigue mechanism of suface nanocrystallined metals,and contribute to a more fully reveal of the deformation behavior and mechanism of the suface nanocrystallined metals,and also promote the development,design and application of the suface nanocrystallined metals.