三维X射线衍射技术与工程材料研究

第三代同步辐射光源可以产生高能X射线,实现对使役条件下工程材料内部晶体结构的原位无损表征。三维X射线衍射(3DXRD)是一种基于同步辐射技术的新兴表征技术,其采用单色高能硬X射线对多晶材料沿不同方向采集衍射信号,得到材料内部晶粒的晶体取向、空间位置、晶内局部应力张量等信息。当结合原位实验对材料进行3DXRD分析时,可以得到各晶粒状态的动态演化。该技术已经在欧洲的ESRF光源、美国的APS光源、日本的SPring-8光源以及德国的DESY光源等的衍射线站应用并向用户开放。综述了3DXRD技术的基本原理及其在工程材料研究中的应用案例,包括测量材料内部晶粒取向的演化、晶粒尺度应力测量、六方晶系材料变形机制研究、材料失效过程研究、晶体塑性有限元模型的验证等。最后基于3DXRD技术的现状,对其发展方向进行了展望。

Three-Dimensional X-ray Diffraction Technique for the Study of Engineering Materials

The third-generation synchrotron radiation source can generate high-energy X-rays to realize in-situ non-destructive characterization of the internal crystal structure of engineering materials under service conditions.As an emerging characterization technique based on synchrotron radiation,three-dimensional X-ray diffraction(3DXRD)technique uses monochromatic high-energy hard X-rays to collect diffraction signals along different directions from polycrystalline materials to obtain the crystal orientation,spatial position,and local stress tensor of the grains inside the material.When the 3DXRD technique is combined with in-situ experiments,the dynamic evolution of the state of each crystal grain can be obtained.This technique has been successfully implemented in synchrotron radiation facilities such as ESRF in Europe,APS in the United States,SPring-8 in Japan and DESY in Germany.This article reviews the working principles of 3DXRD and its applications in engineering materials research,including measuring the evolution of grain orientation in materials,measuring grain-scale stress,studying the deformation mechanisms of hexagonal materials,understanding material failure,and verification of crystal plasticity finite element models.Finally,based on the status of 3DXRD,its development direction is envisioned.