Séminaire de Yubin Zhang

Senior Researcher at the Technical University of Denmark, Department of Civil and Mechanical Engineering.

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Multi-modal 4D X-ray characterization of fracture onset in AA3104

Enlarge the image — Figure 1. Preliminary results for the 3D microstructure of an AA3104 alloy. (a) Grain structure mapped by DCT with intermetallic particles (grey) segmented from PCT data. (b) Tensile strain field at a macroscopic elongation of ~25%, measured by digital volume correlation (DVC). In sub-figure (b), the axes are shown in voxels, with a voxel size of 0.55 µm.

Y. Zhang1*, M. Koboyashi2, H. Fang3, I. Kantor4, M.G. Tarantino5, F. Hild5

1 Department of Civil and Mechanical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark
2 Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan
3 European Synchrotron Radiation Facility, Grenoble, France
4 DanMAX, Max IV, Lund
5 Université Paris-Saclay, CentraleSupélec, ENS Paris-Saclay, CNRS, LMPS - Laboratoire de Mécanique Paris-Saclay, Gif-sur-Yvette, France
*yubz@dtu.dk

Intermetallic particles are inherent to most Al alloys, where they contribute to strengthening while also influencing the microstructure and texture evolution. Despite their critical roles, their interactions with the surrounding Al matrix remain poorly quantified, largely because of the complex three-dimensional nature of the microstructure.
In this study, we establish a multimodal framework to characterize these interactions in a well-annealed AA3104 alloy using two complementary synchrotron X-ray techniques, namely, diffraction contrast tomography (DCT) and phase-contrast tomography (PCT). First, the multimodal approach enables for direct correlation between intermetallic particles mapped by PCT and the Al grain structure mapped by DCT (Figure 1(a)). The results reveal a strong correlation between the grain boundary network and the particle distribution, including particle size and morphology. Second, the influence of intermetallic particles on microstructural evolution during deformation is characterized using PCT during in-situ tensile loading. Digital volume correlation (DVC) is applied to the in-situ 4D datasets to quantify local strain fields and relate it to the surrounding Al microstructure and intermetallic particles (Figure 1(b)). The DVC analysis also enables for the identification of damage nucleation and growth, and their detailed correlation with the local microstructure.

The results highlight the critical need for multimodal characterization techniques to advance the understanding of fracture mechanisms in Al alloys and may support future alloy and process design strategies for improved mechanical properties, particularly for Al alloys produced from recycled scrap. Future directions for the development of multimodal characterization using laboratory-based 4D techniques will also be discussed.