P27

Ti6Al4V

3
Three-Dimensional Analysis of Grains in Electrostatic
Levitation Experimental Samples of Ti6Al4V,,,2,3,4,5,1,Koei KADOI1, Chihiro HANADA1, Yuji MABUCHI1, Yuto UEDA1, Yuta KUSHIYA1, Hirokazu AOKI1,Kanae YONEDA2, Ryosei SAGUCHI2, Motoko YAMADA2, Hisashi SATO2, Yoshimi WATANABE2,Shumpei OZAWA3, Shizuka NAKANO4, Yuki WATANABE5, and Shinsuke SUZUKI1
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2, Waseda University,, Nagoya Institute of Technology,, Chiba Institute of Technology,Henry Monitor, Henry Monitor Inc.,
Advanced Engineering Services (AES)

1.

Introduction
To understand the effects of TiC-induced nucleation in Ti6Al4V alloy, Hetero-3D mission was carried out

in the electrostatic levitation (ESL) furnace. Traditionally, microstructure observations relied on a single crosssection of samples, lacking three-dimensional information for nucleation frequency. By analyzing multiple
sections, it may be possible to connect grain identified as the same across different sections, which could
potentially reveal the three-dimensional arrangement of grains within the sample. The objective of this study
was to devise multiple sections analyses to identify a grain across the multiple-sections.
2.

Experimental Procedures
For sample preparation, the powder of Ti6Al4V with TiC 5 mass% was sintered using spark plasma

sintering (SPS) method and cut with a diamond wire saw into an approximately 30 mg sample. For stablelevitation, the sample was formed into a sphere by arc melting. The sample was melted and solidified using
ESL. For analyses, it was embedded in resin and polished. Electron backscatter diffraction (EBSD) analysis
was conducted to obtain an inverse pole figure (IPF) map to represent the relative orientations of the crystalline
lattices of grains within the cross-section. By grouping measurement points with orientation differences of 5
degrees or less as the same grain, a grain map was generated. The analysis procedures were replicated threetimes on the same sample. Moreover centroid coordinates of sections, crystal orientations and coordinates ofgrains on each cross-section were obtained using the software for EBSD analysis, TSL OIM Analysis 8.

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3. ResultsThe IPF maps for the three cross-sections at depths of 40, 120, and 200 m are presented in Fig. 1.
Furthermore, centroid coordinates of sections, crystal orientations and coordinates of grains are obtained.

Figure 1. IPF maps analyzed across three parallel sections at different depths. When taking the origin at
the top-left corner of each analysis image, the x-axis and y-axis are as indicated in the figure. The
measurements were in units of m. The crystal orientations as Euler angles (1, , 2) arepresented in the upper boxes. These orientations are provided in units of degrees.

4. Discussion
Grain-A in Fig. 1 satisfied the two criteria: (1) Sharing the same plane coordinates, and (2) Having a crystal
orientation difference within 5 degrees. For the first criterion, after adjusting the coordinates of each section
to align the centroid coordinates as the origin (0, 0), it was confirmed that Grain-A possessed the same
coordinates (-214, 549) across all sections. In Fig. 1, the red points represent the locations of these coordinates.
For the second criterion, orientation differences for Grain-A between the 40 - 120 m and 120 - 200 msections were calculated using three Euler angles transformed via the Passive method. Euler angle
differences averaged 1.4 and 3.9 degrees, respectively, within 5 degrees. Therefore, the Grain-A is considered
to exist across three sections.
5. Conclusions
Grain-A in the three cross-sections at depths of 40, 120, and 200 m of the ESL experimental sample wereidentified as the same grain based on the fulfillment of two criteria about coordinates and crystal orientation.
This method may enable the identification of the same grain existing across multiple sections.
Acknowledgements
ESL experiments were conducted with the help of Japan Aerospace Exploration Agency (JAXA). SEMEBSD analyses were supported by Kagami Memorial Research Institute for Materials Science and Technology,Waseda University.
© 2023 by the authors. Submitted for possible open access publication under theterms and conditions of the Creative Commons Attribution (CC BY) license(http://creativecommons.org/li censes/by/4.0/).
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