摘要
以TA19钛合金为研究对象,对端面车削加工所获得的疲劳试样进行20℃室温及400℃高温低周疲劳实验。通过在总疲劳循环次数区间内设置检测节点的方法,分析整个加载过程中表面完整性参数的演变规律。实验结果显示:在室温低周疲劳作用下呈近似脆性断裂,高温低周疲劳作用下呈明显的韧性断裂;室温及高温下,随着疲劳加载周次的增加,表面波纹度振幅与频率均急剧升高;在室温下,表面粗糙度不随疲劳加载周次的增加发生显著变化,而在高温下,表面粗糙度随疲劳加载周次的增加而降低;室温下表面残余压应力几乎不随疲劳加载周次变化,而在高温疲劳的作用下则呈指数形式下降,符合Zener-Wert-Avrami模型。在材料制备和机械加工中,应提高毛坯内部的均匀性,降低加工表面波纹度,增大加工表面残余压应力,以延长在高温疲劳作用下的疲劳寿命。
The purpose of this paper was to reveal the evolution law and mechanism of surface integrity parameters of TA19 titanium alloy end face,and to provide a basis for the process control of blisk surface integrity.Taking faced TA19 titanium alloy fatigue specimens as the research objects,the fatigue tests were carried out at 20℃room temperature and 400℃high temperature.The evolution law of surface integrity parameters during the whole loading process was analyzed by setting detection nodes in the total fatigue cycle number range.The results show that under the action of low cycle fatigue at room temperature,the fracture is near brittle,and under the action of low cycle fatigue at high temperature,the fracture is obviously ductile.The amplitude and frequency of surface waviness increased sharply with the increase of fatigue loading cycles at room temperature and 400℃.Surface roughness is rarely changed under room temperature fatigue tests,but decreased with the increase of fatigue cycles at 400℃.At room temperature,the surface residual compressive stress almost does not change significantly with the increase of fatigue loading cycles,but decreased exponentially at high temperature,which is in accordance with Zener-Wert-Avrami model.Therefore,in the process of material preparation and machining,it is necessary to improve the internal material uniformity of the blank,reduce the corrugation of the machined surface,and increase the amplitude of residual compressive stress on the machined surface,in order to prolong the fatigue life under the action of high temperature fatigue.
作者
丁小岑
何宁
宋迎东
孙志刚
石耀闻
杨吟飞
DING Xiaocen;HE Ning;SONG Yingdong;SUN Zhigang;SHI Yaowen;YANG Yinfei(College of Mechanical and Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;College of Energy and Power Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)
出处
《航空材料学报》
CAS
CSCD
北大核心
2021年第4期57-65,共9页
Journal of Aeronautical Materials
基金
国家科技重大专项(2017-Ⅶ-0001-0094)
国家自然科学基金(52075251)。
