Dataset: The effect of a keyhole defect on strain localisation in an additive manufactured titanium alloy

This is the dataset used in the following publication: S. Cao, R. Thomas, A.D. Smith, P. Zhang, L. Meng, H. Liu, J. Guo, J. Donoghue, D. Lunt, The effect of a keyhole defect on strain localisation in an additive manufactured titanium alloy, Journal of Materials Research and Technology, https://doi.org/10.1016/j.jmrt.2024.11.237 Contained in this dataset are: A Jupyter notebook which uses the open-source DefDAP Python package (https://github.com/MechMicroMan/DefDAP) to open enclosed HRDIC and EBSD data for two regions in an SLM Ti64 sample, one around a keyhole defect and one ~1mm away in the bulk. Please use the 'master' version of DefDAP: https://github.com/MechMicroMan/DefDAP/ Publication abstract: The influence of a keyhole defect on local deformation behaviour in additive manufactured Ti-6Al-4V was investigated by comparing it to a representative bulk region without a defect. High resolution digital image correlation (HRDIC) was used to measure the differences in strain localisation at the microstructural length-scale. A nanoscale speckle pattern was used to allow small changes in strain to be detected and resolved within a single individual lamella and at pre-existing crack locations around the defect. Strain localisation was observed around the defect and formed well below the macroscopic yield stress. In contrast, minimal deformation was found in the bulk at this stress level. Following further deformation into the plastic regime, the strain localisation around the keyhole became more heterogenous with a distinct strain field. A large amount of strain localisation and <c+a> slip was observed either side of the defect normal to the loading direction compared to relatively little in the regions close to the defect in line with the loading direction. This HRDIC observation was consistent with finite element analysis of the expected strain fields around the defect both below and above the yield point. Furthermore, micro-cracks were observed in αp/αp and αp/βt interfaces in both regions with the more pronounced strain fields around the defect leading to an increased number of long micro-cracks than in the bulk. The formation mechanisms of micro-cracks have been discussed, emphasising the role of localised strain caused by the defect.本数据集用于下述学术出版物： S. Cao、R. Thomas、A.D. Smith、P. Zhang、L. Meng、H. Liu、J. Guo、J. Donoghue、D. Lunt，《锁孔缺陷对增材制造钛合金应变局部化的影响》，《材料研究与技术期刊》（Journal of Materials Research and Technology），https://doi.org/10.1016/j.jmrt.2024.11.237 本数据集包含以下内容： 一份Jupyter笔记本，借助开源DefDAP Python包（https://github.com/MechMicroMan/DefDAP）读取封装的高分辨率数字图像相关（High Resolution Digital Image Correlation, HRDIC）与电子背散射衍射（Electron Backscatter Diffraction, EBSD）数据，对应选区激光熔化（Selective Laser Melting, SLM）Ti64试样的两个区域：一个位于锁孔缺陷周边，另一个处于基体中距缺陷约1mm的位置。请使用DefDAP的'master'分支版本：https://github.com/MechMicroMan/DefDAP/ 论文摘要： 本研究通过对比无缺陷的典型基体区域，探究了锁孔缺陷对增材制造Ti-6Al-4V局部变形行为的影响。采用高分辨率数字图像相关（HRDIC）技术，在微观结构尺度下表征应变局部化的差异。实验使用纳米级散斑图案，以实现对单个片层内以及缺陷周边预存在裂纹处的微小应变变化的检测与解析。研究在缺陷周边观测到应变局部化现象，且该现象在远低于宏观屈服应力的载荷下即可形成；与之相对，同一应力水平下基体区域几乎未发生明显变形。随着载荷进一步提升至塑性变形阶段，锁孔周边的应变局部化变得更为不均匀，呈现出独特的应变场分布。相较于沿加载方向邻近缺陷的区域，垂直于加载方向的缺陷两侧出现了大量应变局部化与<c+a>滑移，而该区域的变形程度相对较低。这一HRDIC观测结果与缺陷周边（屈服点上下）的预期应变场有限元分析结果一致。此外，在两个区域的αp/αp与αp/βt界面处均观测到微裂纹，且缺陷周边更强的应变场导致长微裂纹的数量多于基体区域。本文讨论了微裂纹的形成机制，重点强调了缺陷引发的局部应变所起到的作用。