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Novel bulk triaxial residual stress mapping in an additive manufactured bridge sample by coupling energy dispersive X-ray diffraction and contour method measurements
参考中译:通过耦合能量分散X射线散射和轮廓法测量，在增材制造桥梁样本中进行新型体三轴残余应力绘制

刊名：	Additive Manufacturing
作者：	Nicholas A. Bachus（Department of Mechanical and Aerospace Engineering, University of California） Maria Strantza（Lawrence Livermore National Laboratory） Bjorn Clausen（Los Alamos National Laboratory） Christopher R. D'Elia（Department of Mechanical and Aerospace Engineering, University of California） Michael R. Hill（Department of Mechanical and Aerospace Engineering, University of California） J. Y. Peter Ko（Materials Solutions Network at CHESS, Cornell High Energy Synchrotron Source） Darren C. Pagan（Department of Materials Science and Engineering, Pennsylvania State University, University Park） Donald W. Brown（Los Alamos National Laboratory）
刊号：	780C0044/I
ISSN：	2214-8604
出版年：	2024
年卷期：	2024, vol.83
页码：	104070-1--104070-15
总页数：	15
分类号：	TH16
关键词：	Residual stress；Diffraction；Contour method；Additive manufacturing；Titanium
参考中译：	残余应力;折射;轮廓法;增材制造;钛
语种：	eng
文摘：	A novel approach for determining triaxial residual stress states by coupling energy dispersive X-ray diffraction and contour method measurements is provided and validated in a Ti-5Al-5V-5Mo-3Cr additive manufactured (AM) bridge sample. Synchrotron X-ray diffraction (SXRD) can provide relatively fine spatial resolution (on the order of 10-100 μm) for mapping 3D elastic strain fields within a sample. However, for samples with dimensions larger than one or two centimeters the path length can get prohibitive as both constant wavelength and energy dispersive SXRD are based upon transmission measurements. As an example, for a plate-like sample geometry where the thickness is limited (less than a centimeter) it is trivial to measure the longitudinal and height direction elastic strain components with excellent in-plane spatial resolution (～100 μm) and a somewhat lower through-thickness resolution (10-15 times larger) but obtaining the through thickness component is often not possible as the beam path must be parallel to one of the large dimensions of the plate. While small samples of low Z-number alloys (e.g., Ti or Al) allow determination of the three elastic strain components, this is often not the case for higher Z alloys (e.g., Fe or Ni) or large samples where some strain components can be indeterminable. To overcome these limitations, this work applies a combination of synchrotron X-ray diffraction and the contour method (a mechanical relaxation technique), to determine the triaxial stress state. This novel combination is demonstrated and validated in a relatively small additive manufactured sample where all three orthogonal strain components are accessible via X-ray diffraction for stress determination. The paper also explores methods for determining the strain-free lattice parameter, typically obtained from a small stress-free reference sample. This work shows that a small size AM sample is not stress free, producing unreliable magnitudes of strain and stress. Instead, a strain-free lattice parameter is determined using residual stress equilibrium conditions, which gives consistent strain and stress trends for both X-ray diffraction (alone) and the new diffraction-contour coupling technique. This demonstrates that the coupling technique can be confidently applied to samples to determine stress when path length (size or Z-number) prohibit determination of three orthogonal strain components via diffraction.
参考中译：	提出了一种将能量色散X射线衍射法和轮廓法相结合来确定三轴残余应力状态的新方法，并在添加添加剂的Ti-5Al-5V-5Mo-3CR桥试件上进行了验证。同步辐射X射线衍射仪可以提供较高的空间分辨率(约10-100μm)来绘制样品内部的三维弹性应变场。然而，对于尺寸大于一到两厘米的样品，由于恒定波长和能量色散SXRD都基于透射率测量，因此路径长度可能会变得令人望而却步。为了克服这些限制，本工作应用同步加速器X射线衍射和轮廓法(一种机械松弛技术)相结合的方法来确定三轴应力状态。这种新颖的组合在一个相对较小的添加剂制造的样品中得到了演示和验证，其中所有三个正交应变分量都可以通过X射线衍射来确定应力。本文还探索了确定无应变晶格参数的方法，通常是从一个小的无应力参考样品获得的。这项工作表明，小尺寸的AM样品并不是无应力的，会产生不可靠的应变和应力大小。取而代之的是，利用残余应力平衡条件确定了无应变晶格参数，这为X射线衍射和新的衍射-轮廓耦合技术提供了一致的应变和应力趋势。这表明，当路径长度(尺寸或Z数)不允许通过衍射确定三个正交应变分量时，耦合技术可以可靠地应用于样品以确定应力。