Ren Xiaoping, Liu Zhanqiang, Liang Xiaoliang, Cui Pengcheng
School of Mechanical Engineering, Shandong University, Jinan 250061, China.
Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE and Key National Demonstration Center for Experimental Mechanical Engineering Education, Jinan 250061, China.
Materials (Basel). 2021 May 7;14(9):2428. doi: 10.3390/ma14092428.
Machined surface integrity characteristics, including surface stresses, physical-mechanical properties and metallographic structures, play important roles in the fatigue performance of machined components. This work aimed at investigating the effects of machined surface integrity on high-temperature low-cycle fatigue life. The process parameters were optimized to obtain required surface integrity and fatigue life of the turning superalloy Inconel 718. The relationships between low-cycle fatigue life and machined surface integrity characterization parameters were established based on the low-cycle fatigue tests at a high temperature (650 °C). The sensitivities of turning process parameters to high-temperature low-cycle fatigue life were analyzed, and the optimization parameters were proposed with the goal of antifatigue manufacturing. Experimental results indicated that the impact order of the characterization parameters of machined surface integrity on the high-temperature low-cycle fatigue life were the degree of work hardening , the residual stress in the cutting speed direction , the fatigue stress concentration factor , the degree of grain refinement and the residual stress in the feed direction . In the range of turning parameters of the experiments in this research, the cutting speeds could be 80110 m/min, and the feed rate could be 0.100.12 mm/rev to achieve a longer high-temperature low-cycle fatigue life. The results can be used for guiding the fatigue-resistant manufacturing research of aeroengine superalloy turbine disks.
加工表面完整性特征，包括表面应力、物理力学性能和金相组织，在加工部件的疲劳性能中起着重要作用。这项工作旨在研究加工表面完整性对高温低周疲劳寿命的影响。对工艺参数进行了优化，以获得所需的表面完整性和加工高温合金Inconel 718的疲劳寿命。基于高温（650℃）下的低周疲劳试验，建立了低周疲劳寿命与加工表面完整性表征参数之间的关系。分析了车削工艺参数对高温低周疲劳寿命的敏感性，并提出了以抗疲劳制造为目标的优化参数。实验结果表明，加工表面完整性表征参数对高温低周疲劳寿命的影响顺序为加工硬化程度、切削速度方向的残余应力、疲劳应力集中系数、晶粒细化程度和进给方向的残余应力。在本研究实验的车削参数范围内，切削速度可为80110 m/min，进给量可为0.100.12 mm/rev，以获得更长的高温低周疲劳寿命。研究结果可用于指导航空发动机高温合金涡轮盘的抗疲劳制造研究。
