文献类型：期刊文献

英文题名：Fatigue life improvement of cold expanded small holes in a nickel-based superalloy: From process optimization to life prediction

作者：Cheng, Lv-Yi[1];Ju, Ling;He, Kang[1,2];Li, Kai-Shang[1];Gu, Hang-Hang[1];Lei, Xue-Lin[1];Zeng, Fei[2];Li, Wei[2];Zhang, Xian-Cheng[1];Tu, Shan-Tung[1]

机构：[1]East China Univ Sci & Technol, Key Lab Pressure Syst & Safety, Minist Educ, Shanghai 200237, Peoples R China;[2]AECC Hunan Aviat Powerplant Res Inst, Zhuzhou 412002, Peoples R China

年份：2026

卷号：188

外文期刊名：ENGINEERING FAILURE ANALYSIS

收录：;EI(收录号：20260620030332);WOS:【SCI-EXPANDED(收录号:WOS:001686129400001)】；

基金：This work was supported financially by the National Natural Science Foundation of China (52505150) and National Key Research and Development Program (2022YFB4602100) .

语种：英文

外文关键词：Cold expansion process; Small hole structure; Powder metallurgy superalloy; Surface integrity; Fatigue life prediction

摘要：Small hole structures in aerospace components suffer from severe stress concentration and thus cold expansion processes (CEPs) are required to improve fatigue resistance. In this study, a multi-convex rotating CEP was developed to enhance the fatigue performance of vent holes with small diameter of 2.87 mm in a powder metallurgy nickel-based FGH4109 superalloy at 650 degrees C. High-temperature fatigue tests were carried out to verify the CEP-improved effect on fatigue life by over one order of magnitude under certain stress levels. By integrating experimental characterization and Gaussian process regression-expected improvement (GPR-EI) framework, the optimal expansion degree and rotational speed were identified under limited experimental conditions. A weighted comprehensive surface integrity index, combining surface roughness, microhardness, plastic deformation depth, and residual stress, was established and embedded into a modified Smith-Watson-Topper (SWT) model to predict the fatigue life of CEP-treated holes. The proposed framework successfully bridges processing optimization, surface integrity index and fatigue life. The proposed framework not only provides an efficient strategy to optimize CEP parameters and predict fatigue life of hole structures, but also offers a generalizable approach for other surface strengthening processes.