Yin Guang-Qiang, Kang Xia, Zhao Gui-Ping
State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, China.
Institute of Aviation Equipment, Qing'an Group Corporation Limited, Xi'an 710077, China.
Materials (Basel). 2017 Sep 9;10(9):1057. doi: 10.3390/ma10091057.
This paper presents the results of an experiment to investigate the high cycle fatigue properties of the ultra-high strength steel TM210A. A constant amplitude rotating bending fatigue experiment was performed at room temperature at stress ratio R = -1. In order to evaluate the notch effect, the fatigue experiment was carried out upon two sets of specimens, smooth and notched, respectively. In the experiment, the rotating bending fatigue life was tested using the group method, and the rotating bending fatigue limit was tested using the staircase method at 1 × 10⁷ cycles. A double weighted least square method was then used to fit the stress-life (S-N) curve. The S-N curves of the two sets of specimens were obtained and the morphologies of the fractures of the two sets of specimens were observed with scanning electron microscopy (SEM). The results showed that the fatigue limit of the smooth specimen for rotating bending fatigue was 615 MPa; the ratio of the fatigue limit to tensile strength was 0.29, and the cracks initiated at the surface of the smooth specimen; while the fatigue limit of the notched specimen for rotating bending fatigue was 363 MPa, and the cracks initiated at the edge of the notch. The fatigue notch sensitivity index of the ultra-high strength maraging steel TM210A was 0.69.
本文介绍了一项研究超高强度钢TM210A高周疲劳性能的实验结果。在室温下，应力比R = -1的条件下进行了等幅旋转弯曲疲劳实验。为了评估缺口效应，分别对两组试样（光滑试样和缺口试样）进行了疲劳实验。实验中，采用成组法测试旋转弯曲疲劳寿命，采用阶梯法在1×10⁷次循环下测试旋转弯曲疲劳极限。然后使用双加权最小二乘法拟合应力-寿命（S-N）曲线。得到了两组试样的S-N曲线，并用扫描电子显微镜（SEM）观察了两组试样断口的形貌。结果表明，光滑试样的旋转弯曲疲劳极限为615MPa；疲劳极限与抗拉强度之比为0.29，裂纹在光滑试样表面萌生；而缺口试样的旋转弯曲疲劳极限为363MPa，裂纹在缺口边缘萌生。超高强度马氏体时效钢TM210A的疲劳缺口敏感性指数为0.69。
