钛合金TB6连接孔挤压强化残余应力及疲劳寿命试验研究  

Experimental Study on Residual Stress and Fatigue Life of TB6 Titanium Alloy Connection Hole After Cold Expansion

作　　者：冯平法[1,2,3] 刘嘉辉 王子标 冯峰 张翔宇 沈岳[1,2] 张建富 王健健[1,2] 吴志军[1,2] 郁鼎文[1,2] FENG Pingfa;LIU Jiahui;WANG Zibiao;FENG Feng;ZHANG Xiangyu;SHEN Yue;ZHANG Jianfu;WANG Jianjian;WU Zhijun;YU Dingwen(Beijing Key Laboratory of Precision and Ultra-Precision Manufacturing Equipment and Control,Tsinghua University,Beijing 100084,China;State Key Laboratory of Tribology in Advanced Equipment,Tsinghua University,Beijing 100084,China;Tsinghua Shenzhen International Graduate School,Shenzhen 518055,China;State Key Laboratory of Nonlinear Mechanics,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]清华大学精密超精密制造装备及控制北京市重点实验室,北京100084 [2]清华大学高端装备界面科学与技术全国重点实验室,北京100084 [3]清华大学深圳国际研究生院,深圳518055 [4]中国科学院力学研究所非线性力学国家重点实验室(LNM),北京100190

出　　处：《航空制造技术》2023年第11期14-21,共8页Aeronautical Manufacturing Technology

基　　金：国家重点研发计划(2022YFB3405102)。

摘　　要：针对钛合金TB6连接孔,研究直接芯棒挤压强化工艺参数对钛合金耳片的强化效果,表征不同挤压量和挤压次数下连接孔塑性变形量、孔壁残余应力和表面粗糙度,测试挤压强化前后耳片的拉–拉疲劳寿命,分析疲劳断口的形貌特征及疲劳寿命提升的原因。结果表明,挤压强化几乎不能改善孔壁表面质量,但可以使孔壁发生剧烈的塑性变形,引入一定的残余压应力;随着挤压量的增大,塑性变形量增大,残余压应力引入峰值和深度均明显增大,衰减速度减小,而挤压次数的影响相对较小;挤压强化后疲劳寿命显著提高,经由3%挤压量挤压强化后的耳片疲劳极限提升至少38%。Aiming at the connection hole of TB6 titanium alloy,the strengthening effect of cold expansion parameters on titanium alloy lug samples was studied.Plastic deformation,residual stress and surface roughness of the hole expanded with different ratios and times were characterized.The tension-tension fatigue life of lug samples before and after cold expansion was tested.Morphology characteristics of fatigue fracture and the reasons for the improvement of fatigue life were analyzed.The results show that cold expansion can hardly improve the surface quality of the hole,but can cause severe plastic deformation of the hole wall and introduce compressive residual stress.With the increase of expansion ratio,the plastic deformation,the peak value and depth of compressive residual stress increase significantly and the attenuation rate decreases,while expansion times has less impact.The fatigue life of lug samples after cold expansion is significantly improved,and the fatigue limit of cold expansion with 3%expansion ratio is increased by at least 38%.

关 键 词：钛合金TB6 连接孔 挤压强化 残余应力 疲劳寿命 

分 类 号：V262[航空宇航科学与技术—航空宇航制造工程] V215.5