Multiscale residual stress exists throughout the manufacturing process of engineering components,from design and production to processing and servicing.This stress can impact the machin-ing accuracy,structural load capacity,and fatigue lifespan of these components.Therefore,accurate measurement and regulation of residual stress are critical for ensuring the longevity and reliability of en-gineering components.However,precise characterization of residual stress is challenging owing to its multilevel and cross-scale distribution traits and dynamic evolution under various conditions,such as temperature and load.Compared with laboratory X-ray measurement methods,neutron diffraction(ND),synchrotron-based high-energy X-ray diffraction(HE-XRD),and synchrotron-based X-ray microbeam dif-fraction(μ-XRD)techniques offer increased penetration depth and better time and spatial resolutions.In addition,the ability to attach environmental devices enables nondestructive and accurate in situ charac-terization of three types of residual stresses:macroscopic residual stress,intergranular or interphase mi-croscopic stress,and intragranular ultramicroscopic stress.ND is currently the only nondestructive meth-od capable of accurately measuring three-dimensional(3D)stress at centimeter-level depths within engi-neering components.HE-XRD,due to its high flux,excellent collimation,and millimeter-level penetration depth for metals,can be utilized for in situ studies of intergranular and interphase stress evolution and partitioning during deformation.The μ-XRD employs a submicron focused beam and differential aperture technology to analyze depth information of a sample.By conducting point-by-point scanning,it can cap-ture 3D distribution of microscopic stress inside a single grain.Furthermore,our group has developed a novel method and device for depth stress characterization based on differential aperture technology un-der synchrotron-based high-energy monochromatic X-ray transmission geometry,and can measure stress gradients with high precision from the surface to the interior of engineering materials at millimeter-level depths.This study presents the measurement principles,application ranges,and applications of the above-mentioned multiscale stress characterization technologies based on the neutron/synchrotron facili-ties as well as envisaging the future development of related technologies.
维普
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