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New Four-Dimensional Visualization Technique for Analyzing Destruction of Metal Materials (Press Release)

Release Date
10 Jul, 2013
  • BL20XU (Medical and Imaging II)

Kyushu University

A research group led by Hiroyuki Toda (professor) of the Graduate School of Engineering, Kyushu University, developed a new four-dimensional (4D) visualization technique for analyzing metal structures using the world’s most powerful synchrotron radiation facilities of SPring-8. 4D observation means three-dimensional observation over a continuous time axis. With this technique, how metals are deformed upon external loading and finally broken can be observed in detail four-dimensionally. Two-dimensional techniques have been mainly used for research and development of conventional materials. Recently, three-dimensional techniques have been partially used. Because actual phenomena occur four-dimensionally, research and development of materials used for transportation systems such as automobiles and airplanes is expected to markedly advance with the 4D visualization technique. The achievements in this research were published online in a prestigious international journal in the field of metal materials and engineering, Acta Materialia, August issue (No. 61), on 27 June 2013, prior to the printed version (15 July 2013).

Publication:
"Grain boundary tracking technique: four-dimensional"
Hiroyuki Toda, Yoshikazu Ohkawa, Takanobu Kamiko, Takuma Naganuma, Masakazu Kobayashi, Kentaro Uesugi, Akihisa Takeuchi, Yoshio Suzuki
Acta Materialia, 61 14 5535-5548

<<Figures>>

Fig. 1 Experimental setup using BL20XU beamline used for imaging
Fig. 1 Experimental setup using BL20XU beamline used for imaging

Fig. 2 Example of grain boundary tracking
Fig. 2 Example of grain boundary tracking

Only particles on a particular grain boundary are extracted for simplicity (left). The shape of the grain is represented by a polyhedron (middle). Nonuniform deformation of the grain is visualized by tracking the movement of the pixels (right). In practice, all grains existing in a material can be visualized. The morphology of the grains in a material from deformation to complete fracture can be observed.

Fig. 3 Principle of grain boundary tracking technique
Fig. 3 Principle of grain boundary tracking technique

Images obtained using facilities at SPring-8 (light blue area). How a material is deformed and broken is observed four-dimensionally. Finally, a dissimilar metal is doped into the grain boundary to obtain a grain boundary image. Using this image, whether all the particles that can be visualized are on the grain boundary or not is determined. Then, the grain is represented by a polyhedron using all grain boundary particles as apices (upper right of the green area). The movement of the grain boundary pixels (normally 20,000-30,000) during the deformation of the material is determined by image analysis by going back in time (upper side of the green area). A subtle deformation of the grain can also be collaterally visualized by tracking the movement of the particles (lower side of the green area).

Fig. 4 Example of grain boundary tracking
Fig. 4 Example of grain boundary tracking

Only pixels on a particular grain boundary are extracted for simplicity. The deformation behavior of a grain under external loading is represented by arrows.

Fig. 5 Morphology of eight grains and their deformation behavior represented on virtual cross section
Fig. 5 Morphology of eight grains and their deformation
behavior represented on virtual cross section

The entire material is uniformly subjected to a simple tensile load. However, the deformation at the grain level is very complicated and the degree of deformation differs depending on the position of the grain.


For more information, please contact:
  Prof. Hiroyuki Toda (Kyushu University)
    E-mail : mail1
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