OS2-1
Hetero-3D ミッションにおける TiC を添加した
Ti 合金試料の ISS-ELF による溶融凝固実験の飛行後解析
Postflight Analyses of Melting and Solidification
Experiments of Ti Alloy Samples with TiC by ISS-ELF in
Hetero-3D Mission
鈴木進補 1, 門井洸衛 1, 櫛舎祐太 1 , 上野遥か 1 , 上田雄翔 1, 馬渕勇司 1, 花田知優 1,
山田素子 2, 左口凌成 2, 佐藤 尚 2, 渡辺義見 2, 小澤俊平 3, 谷本滉平 4, 白鳥 英 4,
中野 禅 5, 渡邊勇基 6, 織田裕久 7, 小山千尋 7, 池内留美子 7, 下西里奈 7, 石川毅彦 7
Shinsuke SUZUKI 1, Koei KADOI 1, Yuta KUSHIYA 1, Haruka UENO 1, Yuto UEDA 1,Yuji MABUCHI 1, Chihiro HANADA 1, Motoko YAMADA 2, Ryosei SAGUCHI 2,Hisashi SATO 2, Yoshimi WATANABE 2, Shumpei OZAWA 3, Kohei TANIMOTO 4,Suguru SHIRATORI 4, Shizuka NAKANO 5, Yuki WATANABE 6, Hirohisa ODA 7,
Chihiro KOYAMA 7, Rumiko IKEUCHI 7, Rina SHIMONISHI 7, and Takehiko ISHIKAWA 7
早稲田大学, Waseda University,名古屋工業大学, Nagoya Institute of Technology,
3 千葉工業大学, Chiba Institute of Technology,
4 東京都市大学, Tokyo City University,
5 株式会社 Henry Monitor, Henry Monitor Inc.,
6 株式会社エイ・イー・エス, Advanced Engineering Services (AES),
7 宇宙航空研究開発機構, Japan Aerospace Exploration Agency (JAXA)
12

1.

Introduction
The mission of the JAXA's science experimental theme “Heterogeneous solidification behavior of powder

metals for 3D printer” (Abbreviation: Hetero-3D, PI: S.Suzuki, Waseda University) is being carried out1, 2). The
objective of this mission is to clarify the effects of heterogeneous nucleation site particles on solidification
behavior of metals for 3D printing. For this objective, melting and solidification experiments with Electrostatic
Levitation Furnace in International Space Station (ISS-ELF) are an ideal method to exclude the effects ofcontamination from the container, evaporation and natural convection. The obtained results will be applied
to improve the physical properties of the products built by 3D printer through refinement of crystal grains byheterogeneous nucleation site particles added in metallic powder3). The overview of this mission is shown inFig.1. Through preflight experiments and simulations, important results have already been obtained on
appropriate sample preparation methods 4), heating conditions 5), recording conditions by high-speed camera6),
and temperature and velocity fields in samples7).
On-board melting and solidification experiments of Ti and Ti alloys with and without TiC heterogeneous
nucleation site particles were performed with ISS-ELF as planned in April and May 2023. The samples werereturned to the ground in June 2023. The details of the on-board experiments have already been presented at
1 of 3the previous conference JASMAC-35 2).
Currently the flight samples and telemetry data are being analyzed. This presentation introduces the results
obtained through postflight analyses and applications of the results to clarification of the solidification
behavior including nucleation and crystal growth.

Figure 1 Overview of mission Hetero-3D2.

Analyses of Flight Samples and Telemetry Data
A cross section of a flight sample Ti-6Al-4V with 5 mass% TiC was polished and analyzed by electronbackscatter diffraction (EBSD). By calculation using Voronoi tessellation the number of prior- grains wasestimated to be 299 8).
On the surface of the flight sample, streak patterns were observed by scanning electron microscopy (SEM),
which were not found on the samples of the electrostatic levitation experiments on the ground. As a result, astreak was found to be a step of height difference lying along the prior- grain boundary 9).
Telemetry data of movies captured by high-speed camera was analyzed. As a result of a Ti-6Al-4V with 2
mass% TiC, the growth rate of a prior- grain and its relative error were estimated to be 3 – 5 mm･s-1 and10.2%, respectively 10).
Observation using X-ray computed tomography (X-ray CT) imaging is being prepared to obtain 3D grain
mappings of flight samples with the synchrotron radiation facility SPring-8.
From these results, the solidification mechanism will be clarified for the ISS-ELF experiments, as has been
done in other levitation experiments 11).

3.

Modelling of Solidification Behavior
The dissolution model was established to estimate the number of TiC particles which work as the nucleationsites (Active-TiC) 12). When the estimated number of Active-TiC particles is input to the Phase-field simulation,
the number of the prior- grain can be calculated. By varying the unknown parameter such as seed (possiblenucleation site) density, mobility and so on, the simulated results of degree of undercooling for nucleation
onset and number of prior- grains can be adjusted to the experimental ones. By this procedure, the nucleationand crystal growth are visualized and the physical meanings of the adjusted parameters are discussed 13).
2 of 3References
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© 2024 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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