腐蚀条件下高强钢超高周疲劳性能及损伤机理研究进展

Research Progress on Very High Cycle Fatigue Performance and Damage Mechanism of High Strength Steel Under Corrosion Condition

在疲劳载荷作用下,材料发生裂纹萌生、扩展直至断裂的周次在107以上的过程被称为超高周疲劳。部分高强钢机械部件需在恶劣环境中服役,服役期间承受的疲劳载荷周次高达108~1011,高强钢在腐蚀环境中的超高周疲劳问题成为影响结构可靠性、安全性的关键问题,是航空航天、汽车、高铁等领域亟待解决的难点。得益于金属材料在传统疲劳问题上的总结积累与先进试验手段的助力,诸多学者开发出多种新的试验方法,有针对性地对高强钢在腐蚀条件下的超高周疲劳问题展开研究。目前,关于腐蚀条件下高强钢超高周疲劳性能退化规律及损伤机理、腐蚀条件下裂纹萌生竞争机制及裂纹初期扩展行为、氢对高强钢超高周疲劳性能及颗粒亮面形成机制的影响等核心问题的认识愈发清晰,逐渐从对试验现象的描述与归纳深入到对损伤机理的探索与推演,而且部分研究成果已经逐步在工程实践中得到应用。本文首先从S-N曲线等角度简述了高强钢无腐蚀条件下的超高周疲劳损伤特征;然后总结了典型腐蚀介质对高强钢超高周疲劳性能的影响,并指出氢脆断裂为高强钢在腐蚀环境中的断裂机理之一;随后详述了氢对高强钢超高周疲劳性能及颗粒亮面形成机制的影响研究进展;最后对几个关键问题进行了展望。

The process of crack initiation,propagation and fracture with more than 107 cycles under fatigue load is called very high cycle fatigue.Parts of machines made of high strength steel need to be used in corrosive environment,and they need to bear up to 108-1011 fatigue loads during the service life.The problem of very high cycle fatigue of high strength steel in corrosive environment has become a key problem affecting the reliability and safety of structures,and it has become an urgent difficulty to be solved in aerospace,automobile,high-speed railway and other fields.Thanks to the summary and accumulation of metal materials on traditional fatigue problems and the help of advanced test methods,many scholars have developed a variety of new test methods to study the very high cycle fatigue of high strength steel under corrosive conditions.At present,the core problems such as the degradation law and damage mechanism of very high cycle fatigue properties of high strength steel under corrosive conditions,the competition mechanism of crack initiation and initial crack propagation behavior under corrosive conditions,and the effect of hydrogen on very high cycle fatigue properties of high strength steel and the formation mechanism of granular bright facet are becoming more and more clear.Moreover,some research results have been gradually applied in engineering practice.In this review,the very high cycle fatigue damage characteristics of high strength steel without corrosion are briefly described from the perspec-tive of S-N curve.Then the effects of typical corrosive media on very high cycle fatigue properties of high strength steel are summarized,also it is pointed out that hydrogen embrittlement fracture is one of the fracture mechanisms of high strength steel in corrosive environment.Then,the re-search progress of hydrogen on very high cycle fatigue properties of high strength steel and the formation mechanism of granular bright facet are described in detail.Finally,several key issues are prospected.