Strain mapping of individual grains using diffraction contrast tomography

使用衍射对比断层扫描技术绘制单个晶粒的应变图

• 批准号: EP/F020910/1
• 负责人: Michael Preuss
• 金额: $ 15.98万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FF020910%2F1
• 关键词: Strain; mapping; individual; grains; using

This research project will aim to undertake a fundamental study of the early stages of plastic deformation in two types of polycrystalline alloys, low interstitial steel and commercially pure titanium (each material has a very distinct crystal structure, which has a strong impact on the deformation mechanisms), by using diffraction contrast tomography (DCT) on high-energy synchrotron x-ray radiation beam lines. Diffraction contrast tomography is a novel polycrystal grain and orientation mapping technique, which allows one to simultaneously characterize nondestructively and in 3D the grain shape and crystallographic orientation of a large number of grains in a polycrystalline material. This technique has been implemented at the European Synchrotron Radiation Facility (ESRF) beamline ID19 only very recently and substantial progress in terms of data analysis has led to the reconstruction of 1000 grains in aluminum and steel samples. To date, all diffraction contrast tomography work has been on fully recrystallised and undeformed material due to the limited contrast and diffused diffraction spots when working with material of high mosaicity. The aim of this project is to take DCT to the next level enabling the measurement the development of elastic strain between individual grains during the onset of plastic deformation. This elastic strain develops due to the crystallographic anisotropy of grains and can be used to study deformation mechanisms. Such measurements will be achieved by enhancements of the scanning procedures during DCT experiments and advances in the data analysis routine. The data recorded in this way will for the first time provide grain to grain strain/stress information, which can be used to develop and validate crystal plasticity finite element modeling.

该研究项目旨在对两种多晶合金、低间隙钢和商业纯钛的塑性变形的早期阶段进行基础研究（每种材料都具有非常独特的晶体结构，这对变形机制有很大影响） ），通过在高能同步加速器 X 射线辐射束线上使用衍射衬度断层扫描 (DCT)。衍射对比断层扫描是一种新颖的多晶晶粒和取向映射技术，它允许人们同时以非破坏性和 3D 方式表征多晶材料中大量晶粒的晶粒形状和晶体取向。这项技术最近才在欧洲同步辐射装置 (ESRF) 光束线 ID19 上实施，数据分析方面的重大进展已经导致铝和钢样品中 1000 个晶粒的重建。迄今为止，所有衍射衬度断层扫描工作都是在完全再结晶和未变形的材料上进行的，因为在使用高镶嵌度材料时对比度有限且衍射点扩散。该项目的目标是将 DCT 提升到一个新的水平，从而能够测量塑性变形开始期间各个颗粒之间弹性应变的发展。这种弹性应变是由于晶粒的晶体各向异性而产生的，可用于研究变形机制。这种测量将通过 DCT 实验期间扫描程序的增强和数据分析程序的进步来实现。以这种方式记录的数据将首次提供晶粒间的应变/应力信息，可用于开发和验证晶体塑性有限元模型。

项目成果

Twinning in Ti-4at.% Al studied by Diffraction Contrast Tomography

孪晶%20in%20Ti-4at.%%20Al%20研究%20by%20衍射%20对比度%20断层扫描

• 作者: Preuss, M.

Comparison between a near-field and a far-field indexing approach for characterization of a polycrystalline sample volume containing more than 1500 grains

• DOI: 10.1107/s160057671401406x
• 发表时间: 2014-08
• 期刊: Journal of Applied Crystallography
• 影响因子: 6.1
• 作者: Laura Nervo;A. King;Jonathan P. Wright;W. Ludwig;P. Reischig;J. Q. D. Fonseca;M. Preuss

A study of deformation twinning in a titanium alloy by X-ray diffraction contrast tomography

• DOI: 10.1016/j.actamat.2015.12.032
• 发表时间: 2016-02-15
• 期刊: ACTA MATERIALIA
• 影响因子: 9.4
• 作者: Nervo, Laura;King, Andrew;Preuss, Michael
• 通讯作者: Preuss, Michael

A feasibility study of full-field X-ray orientation microscopy at the onset of deformation twinning

变形孪生开始时全视场 X 射线定向显微镜的可行性研究

• DOI: 10.1107/s1600576716002302
• 发表时间: 2016
• 期刊: Journal of Applied Crystallography
• 影响因子: 6.1
• 作者: Viganò N