微动腐蚀疲劳中的化-力学效应及多尺度损伤机理研究

项目名称： 微动腐蚀疲劳中的化-力学效应及多尺度损伤机理研究

项目编号： No.51275225

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 机械、仪表工业

项目作者： 李淑欣

作者单位： 兰州理工大学

项目金额： 68万元

中文摘要： 采用榫槽结构的汽轮机末级叶片，由于振动和腐蚀的共同作用，腐蚀环境下的微动疲劳是影响结构安全性和完整性的主要因素之一。本项目采用宏微观实验测试和理论分析相结合，研究腐蚀环境中接触力-电化学-疲劳载荷交互作用下叶片材料的微动疲劳性能。建立不同尺度的微动腐蚀疲劳损伤模型，深入理解其损伤机理。研究力-化学作用下微动疲劳不同阶段的裂纹萌生和扩展的主导机制，掌握小裂纹发展至扩展裂纹的机理和条件。通过本课题的研究可以更准确地评价汽轮机叶片材料微动疲劳性能及其主要影响因素。同时，对提出更加合理的防微动疲劳失效措施以及不锈钢榫槽结构的安全可靠的长周期运行具有重要的理论意义和实际应用价值。

中文关键词： 榫槽结构；；微动疲劳；；微动磨损；；裂纹止裂；；剪切带

英文摘要： Fretting fatigue in corrosive environment is one of the main factors affecting the safety and integrity of the dovetail structure of the last blade in steam turbine due to the vibration and humid steam working environment. Combined with the experimental testing on micro and macro levels and the theoretical analysis, the fretting corrosion fatigue behavior of steam turbine blades under interactive action of contact stress, electrochemical and fatigue loading is investigated in the project. Multi-scale fretting corrosion fatigue damage models will be proposed to clearly understand the fretting fatigue damage mechanism on both micro and macro scales. The dominant mechanisms on crack initiation and propagation at various stages in fretting fatigue will be investigated to find out the mechanism and the critical condition for small-to-long crack transition. By conducting the present study, the fretting fatigue properties of steam turbine blade materials and key parameters affecting these properties will be better evaluated. Meanwhile, the study will be helpful for providing a reasonable anti fretting fatigue measures for blade material of stainless steel dovetails and fittings, which is of great importance theoretically and practically to ensure long term safe operation.

英文关键词： Dovetail;；Fretting fatigue;；Fretting wear;；Crack arrest;；Contact shear band.