摘要
多尺度残余应力贯穿于工程部件设计、生产、加工和服役的全生命周期,对工程部件的长寿命可靠服役具有重要意义.残余应力具有多层次、跨尺度的分布特征,在温度、载荷等服役环境作用下发生动态演化,给精确表征带来了很大困难.相较于传统实验室X射线残余应力测量方法,中子衍射、同步辐射高能X射线衍射和同步辐射微束衍射技术在穿透深度、时间分辨率、空间分辨率、环境装置等方面具有显著优势,能够实现宏观残余应力、晶间/相间微观应力、晶内超微观应力3类残余应力的原位无损精确表征.本文详细介绍了上述基于中子/同步辐射大科学装置的多尺度应力表征技术的测量原理、应用范围和典型应用案例,并对相关技术的发展进行了展望.
Abstract
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.
基金项目
国家重点研发计划项目(2021YFA1600600)
国家自然科学基金(U2141206)
国家自然科学基金(52171098)
国家自然科学基金(51921001)
维普
万方数据