旋转弯曲和超声波循环加载高周疲劳性能对比分析  

Research of rotating and ultrasonic cycling fatigue in high-cycle regimes

作　　者：刘璐 王生楠[1] 马一凡[1] LIU Lu;WANG Shengnan;MA Yifan(School of Aeronautics,Northwestern Polytechnical University,Xi’an 710072,China;School of Aircraft,Xi’an Aeronautical Institute,Xi’an 710077,China)

机构地区：[1]西北工业大学航空学院,西安710072 [2]西安航空学院飞行器学院,西安710077

出　　处：《航空材料学报》2024年第3期142-150,共9页Journal of Aeronautical Materials

基　　金：国家自然科学基金项目(12072272)。

摘　　要：通过旋转弯曲(频率52.5 Hz,10^(3)~10^(8)周次)和超声波(频率20 kHz,5×10^(4)~10^(9)周次)轴向循环载荷疲劳实验,研究不同应力比(R)、加载方式和夹杂物对CL60钢高周、超高周疲劳性能的影响。结果表明:所有S-N曲线均呈现水平渐进趋势,并具有明确的疲劳极限;应力比R=-1情况下,通过超声波实验获得的疲劳强度(260~270MPa)比旋转弯曲获得的疲劳强度(400~410 MPa)低140~150 MPa,并且应力比R=0.3的超声波疲劳极限值在195~205 MPa的范围内;旋转弯曲疲劳实验的疲劳裂纹起源于试件的表面,超声波疲劳实验的表面和内部均有裂纹萌生,且裂纹均在MnS夹杂物附近产生,与应力比大小无关。采用有限元方法研究了MnS夹杂物对裂纹萌生和扩展的影响,椭圆MnS夹杂物的侧面相较于尖端位置应力集中水平更高,导致裂纹从夹杂物侧面萌生。The effects of stress ratio(R),loading condition,and MnS inclusion on the fatigue behavior of medium-carbon pearlitic high strength steel were investigated by the combination of rotating(frequency of 52.5 Hz,10^(3)-10^(8))bending and ultrasonic(frequency of 20 kHz,5×10^(4)-10^(9))axial cycling tests in high-cycle and very-high-cycle regimes.The study results show that all the S-N curves present horizontal asymptotic shapes and have clear fatigue limits.The fatigue limits(260-270 MPa)for R=−1 obtained by ultrasonic test are 140-150 MPa,which are lower than that(400-410 MPa)obtained by rotating bending,and the limit values for R=0.3 are in the range of 195-205 MPa.For rotating bending,the fatigue fractures are originated from the surface matrix of the specimen,whereas for ultrasonic fatigue,both surface and interior crack initiation occur,and cracks are all initiated from MnS inclusions regardless of stress ratios.The influence of MnS inclusions on crack initiation and propagation is studied by finite element method.The side of elliptical MnS inclusions has higher stress concentration than the tip position,which leads to crack initiation from the side of inclusions.

关 键 词：CL60钢 高周疲劳 应力比 夹杂 超声波循环 

分 类 号：V216.3[航空宇航科学与技术—航空宇航推进理论与工程] TB3[一般工业技术—材料科学与工程]