Lai Fuqiang, Mao Kun, Cao Changsheng, Hu Anqiong, Tu Junxiang, Lin Youxi
School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China.
Materials (Basel). 2023 Jan 13;16(2):815. doi: 10.3390/ma16020815.
The purpose of this paper is to investigate the fatigue properties of C17200 alloy under the condition of quenching aging heat treatment at high temperatures, and to provide a design reference for its application in a certain temperature range. For this purpose, the tensile and rotary bending fatigue (RBF) tests were carried out at different temperatures (25 °C, 150 °C, 350 °C, and 450 °C). The tensile strength was obtained, and relationships between the applied bending stress levels and the number of fatigue fracture cycles were fitted to the stress-life (S-N) curves, and the related equations were determined. The fractured surfaces were observed and analyzed by a scanning electron microscopy (SEM). The results show that the RBF fatigue performance of C17200 alloy specimens is decreased with the increase in test temperature. When the temperature is below 350 °C, the performance degradation amplitudes of mechanical properties and RBF fatigue resistance are at a low level. However, compared to the RBF fatigue strength of 1 × 10 cycles at 25 °C, it is decreased by 38.4% when the temperature reaches 450 °C. It is found that the fatigue failure type of C17200 alloy belongs to surface defect initiation. Below 350 °C, the surface roughness of the fatigue fracture is higher, which is similar to the brittle fracture, so the boundary of the fracture regions is not obvious. At 450 °C, due to the further increase in temperature, oxidation occurs on the fracture surface, and the boundary of typical fatigue zone is obvious.
本文旨在研究C17200合金在高温淬火时效热处理条件下的疲劳性能，为其在一定温度范围内的应用提供设计参考。为此，在不同温度（25℃、150℃、350℃和450℃）下进行了拉伸和旋转弯曲疲劳（RBF）试验。获得了抗拉强度，将施加的弯曲应力水平与疲劳断裂循环次数之间的关系拟合到应力-寿命（S-N）曲线，并确定了相关方程。通过扫描电子显微镜（SEM）对断口进行了观察和分析。结果表明，C17200合金试样的RBF疲劳性能随试验温度的升高而降低。当温度低于350℃时，力学性能和RBF疲劳抗力的性能退化幅度处于较低水平。然而，与25℃时1×10次循环的RBF疲劳强度相比，当温度达到450℃时，其降低了38.4%。发现C17200合金的疲劳失效类型属于表面缺陷萌生。在350℃以下，疲劳断口的表面粗糙度较高，类似于脆性断裂，因此断裂区域的边界不明显。在450℃时，由于温度进一步升高，断口表面发生氧化，典型疲劳区的边界明显。
