A physically-based representative stress methodology for predicting stress rupture life of Ni-based DS superalloy  

作　　者：Jia HUANG Zhenzhuo HE Shuangqi LYU Xiaoguang YANG Duoqi SHI Yantao SUN Yongzhao LYU Zhizhong FU Guolei MIAO Jianan SONG 

机构地区：[1]School of Aeronautics and Astronautics,Central South University,Changsha 410083,China [2]Aviation Engineering College,Civil Aviation University of China,Guanghan 618307,China [3]School of Energy and Power Engineering,Beihang University,Beijing 100083,China [4]Beijing Aeronautical Engineering Technical Research Center,Beijing 100076,China [5]Chengdu Holy Industry&Commerce Corp.LTD,Pengzhou 611936,China [6]School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China

出　　处：《Chinese Journal of Aeronautics》2023年第6期174-185,共12页中国航空学报（英文版）

基　　金：the funding of Natural Science Foundation of Hunan Province, China (No. 2021JJ40741);Fundamental Research Funds for the Central Universities of Central South University (No. 2021zzts0911);National Science and Technology Major Project (No. J2019-IV-0017-0085)

摘　　要：Smooth and three types of U-shape single-edge notched plate specimens adopted to experimentally investigate stress rupture behavior of Ni-based Directionally Solidified(DS)superalloy at 850℃ exhibit notch weakening effect and multi-source cracking initiation near the notch root.However,stress rupture behavior of smooth and V-shape notched round bars at 1040℃ revealed by Li et al indicates notch strengthening effect and creep micro-holes originating mostly from the central portion.A combined creep-viscoplastic constitutive model is employed to analyze the distribution of stress,strain and stress Triaxial Factor(TF)near the notch root.The different stress distribution and creep restraint between asymmetric notched plate specimens and symmetric notched round bars are the main reasons for the corresponding failure mechanism.Meanwhile,a good qualitative relationship exists between TF value and stress rupture life of notched specimen.Especially,the area with maximum TF value(TF_(max))is highly consistent with creep damage initiation region.Hence,based on the distribution characteristics of the initial tensile loading,a representative stress method independent of time-changing creep load at the location of TF_(max) is conducted for life prediction.The predicted results of both smooth and notched plate specimens and round bars agrees well with the experimental results.

关 键 词：CREEP Life model Ni-based superalloy Notched round bar Single edge notch 

分 类 号：V252.2[一般工业技术—材料科学与工程]