With the continuous advancement of aerospace technology,ensuring the reliability of aerospace engines after testing is critical.While various methods exist for assessing fatigue life,non-destructive prediction based o...With the continuous advancement of aerospace technology,ensuring the reliability of aerospace engines after testing is critical.While various methods exist for assessing fatigue life,non-destructive prediction based on insitu X-ray diffraction(XRD)residual stress analysis remains underexplored—particularly for low-cycle fatigue in welded joints.This study proposes a novel approach that uses in-situ XRD to monitor residual stress evolution under fatigue and creep loading in gas tungsten arc welding(GTAW)joints of aerospace-grade austenitic stainless steel SUS321.Through metallographic observation,scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),and in-situ XRD measurements,we demonstrate a strong correlation between longitudinal residual stress at the weld center and fatigue life.Under fatigue loading at 60%of the ultimate tensile strength(UTS),longitudinal residual stress transitions from tensile to compressive with increasing cycles,and fatigue fracture occurs once residual stress approaches base metal levels(∼0 MPa).In contrast,under creep loading,no clear trend in Y-direction residual stress was observed,limiting its utility for creep life prediction.This work establishes a reliable,non-destructive framework for evaluating the service life of welded aerospace components,offering a new methodology beyond conventional practices.展开更多
基金supported by the Fundamental Research Funds for the Central Universities,the Institute of Marine Equipment,the Shanghai Rising-Star Program of Science and Technology Commission of Shanghai Municipality(Grant No.23QA1404700)National Natural Science Foundation of China(Grant Nos.52475384,52505409)China Postdoctoral Science Foundation(Grant No.2024M761963).
文摘With the continuous advancement of aerospace technology,ensuring the reliability of aerospace engines after testing is critical.While various methods exist for assessing fatigue life,non-destructive prediction based on insitu X-ray diffraction(XRD)residual stress analysis remains underexplored—particularly for low-cycle fatigue in welded joints.This study proposes a novel approach that uses in-situ XRD to monitor residual stress evolution under fatigue and creep loading in gas tungsten arc welding(GTAW)joints of aerospace-grade austenitic stainless steel SUS321.Through metallographic observation,scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),and in-situ XRD measurements,we demonstrate a strong correlation between longitudinal residual stress at the weld center and fatigue life.Under fatigue loading at 60%of the ultimate tensile strength(UTS),longitudinal residual stress transitions from tensile to compressive with increasing cycles,and fatigue fracture occurs once residual stress approaches base metal levels(∼0 MPa).In contrast,under creep loading,no clear trend in Y-direction residual stress was observed,limiting its utility for creep life prediction.This work establishes a reliable,non-destructive framework for evaluating the service life of welded aerospace components,offering a new methodology beyond conventional practices.
