Effects of microstructures on deformation and damage of thermomechanical fatigue in nickel-base single crystal superalloys  

作　　者：Cheng LUO Huang YUAN 

机构地区：[1]School of Aerospace Engineering,Tsinghua University,Beijing 100084,China [2]Institute of Aero Engines,Tsinghua University,Beijing 100084,China

出　　处：《Chinese Journal of Aeronautics》2025年第2期541-558,共18页中国航空学报(英文版)

基　　金：financed by the National Natural Science Foundation of China(Nos.12402071,92160204);the China Postdoctoral Science Foundation(No.2024M751635);the Postdoctoral Fellowship Program of CPSF,China(No.GZB20240365);the National Science and Technology Major Projects of China(No.J2019-IV-0011-0079).

摘　　要：Thermomechanical Fatigue (TMF) is one of the most dangerous failure modes of high-temperature structures. The effect of coarsened and rafted microstructures on the TMF behavior of Nickel-Base Single Crystal Superalloys (NBSX) was experimentally studied. TMF tests under In-Phase (IP) and Out-of-Phase (OP) paths revealed significant variations in TMF life reduction. Cyclic deformation behaviors of alloys with different microstructures were compared. The effect of microstructure on TMF damage mechanisms was unveiled from characterizations of fracture surfaces and longitudinal sections by scanning electronic microscope and optical microscope. A transition from mode-I to crystallographic fracture in the coarsened alloy during IP-TMF was observed and discussed. Due to the degraded microstructure, the dispersed distribution of crystal slips was distinguished in the coarsened and rafted alloys. The competitive or synergetic interactions among oxidation-assisted mode-I opening, casting pore-related mode-I creep and crystallographic slipping were discussed. This study underscores the complex interplay among microstructure, deformation behaviors and damage mechanisms, offering valuable insights into alloy performance under TMF conditions.

关 键 词：Thermomechanical fatigue Rafting and coarsening Single crystal superalloy Damage mechanism Life reduction Fatigue-creep-oxidation 

分 类 号：TG1[金属学及工艺—金属学]