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Latest 30 articles

2025.10.09

【受賞】宮澤君が、日本チタン学会講演大会（2025年度）（直江津）にて、最優秀ポスター賞を受賞しました。

宮澤啓太郎、小笹良輔、中野貴由：
最優秀ポスター賞、L-PBFにおける窒素ガス雰囲気を利用したTi-42Nb合金の高強度化、
第5回日本チタン学会講演大会（2025年度）、日本チタン学会、
2025年10月10日、直江津学びの交流館

2025.10.09

【学会】第5回日本チタン学会講演大会（2025年度）（＠直江津学びの交流館、10月9,10日）に参加し、以下の発表を行いました。

一般講演
〇小笹良輔、中野貴由:
L-PBFによるTi基合金の組成に応じた微細組織と力学特性の制御

〇Ozkan Gokcekaya, Takayoshi Nakano:
Design of Bio High-Entropy Alloys with Suppressed Elemental Segregation for Laser Powder Bed Fusion Process

ポスターセッション
〇宮澤啓太郎、小笹良輔、中野貴由:
L-PBFにおける窒素ガス雰囲気を利用したTi-42Nb合金の高強度化

2025.09.29

2025年9月29日　【講演】中野先生がセラミックス3D積層造形研究会 2025年度第1回研究会にて講演を行いました。

中野貴由先生が、一般社団法人日本ファインセラミックス協会にて開催された「セラミックス3D積層造形研究会 2025年度第1回研究会」において、「結晶性材料の積層造形による形状・結晶配向性制御と骨医療デバイス応用」と題したご講演を行いました。

PDFはこちら

2025.09.26

【受賞】日本金属学会2025年（第177回）秋期講演大会ポスターセッションにて、M1の竹下君、M2の内芝君が優秀ポスター賞を受賞しました。

特異な直交性⾻基質配向化制御機構の解明と⽣体組織配向性への影響
○⽵下恭平、中⻄陽平、松坂匡晃、松垣あいら、中野貴由
第45回優秀ポスター賞、北海道大学、2025年9月17日

レーザ粉末床溶融結合を⽤いたTi準結晶の創製と組織解析
○内芝旭祥、⼩笹良輔、佐藤和久、中野貴由
第45回優秀ポスター賞、北海道大学、2025年9月17日

2025.09.24

【お祝い】中野研究室のメンバーで中野先生の58歳の誕生日をお祝いしました。

2025年9月22日に中野先生が58歳の誕生日を迎えられました。研究室のメンバー一同でケーキを用意し、日頃のご指導への感謝を込めてお祝いしました。

2025.09.23

【論文編集】中野先生がAdditive Manufacturingをはじめとした材料開発と新プロセスに関する新規の論文誌、"Journal of Innovations in Materials and Manufacturing Engineering (JIMME)" の編集委員に就任しました。オーストラリアのScilight Pressから出版され、チーフエディターはテキサス大のProf. L. E. Murrです。

中野先生がAdditive Manufacturingをはじめとした材料開発と新プロセスに関する新規の論文誌、"Journal of Innovations in Materials and Manufacturing Engineering (JIMME)" の編集委員に就任しました。オーストラリアのScilight Pressから出版され、チーフエディターはテキサス大のProf. L. E. Murrです。

AIMS
Journal of Innovations in Materials and Manufacturing Engineering (JIMME) is an international, peer-reviewed, multidisciplinary journal that provides a platform for disseminating high-quality original research and critical reviews in materials and manufacturing engineering. The journal serves both the academic and industrial communities, fostering the exchange oof cutting-edge knowledge and innovations. It aims to highlight contemporary advances and future developments, with particular emphasis on the practical applications of novel materials and manufacturing technologies. It is published quarterly online by Scilight Press, Melbourne, Australia.
Scope of the Journal
JIMME covers a broad range of topics encompassing new materials, processes, and technologies applied to manufacturing engineering and product development, with special focus on innovations in additive manufacturing and related emerging processes. Topics of interest include, but are not limited to:
• Novel materials development, synthesis, applications, and methodologies in advanced manufacturing processes, particularly across the full spectrum of 3D printing technologies.
• Multifunctional material and device design, covering metals and alloys (including high-entropy alloys, superalloys, and superplastic alloys), composite materials, electronic and optical materials, nanomaterials, biomaterials, 2D materials, and other advanced material systems.
• Innovations in materials processing, including hybrid and multi-material manufacturing approaches.
• Characterization, optimization, and simulation of materials and manufacturing processes, with an emphasis on modelling, artificial intelligence-driven design, and digital manufacturing applications

2025.09.17

【学会】日本金属学会2025年（第177回）春期講演大会（@北海道大学、9月17日～9月19日）に参加しています。

中野研究室のメンバー（＋名工大萩原教授、富山大松田教授、富山大石本先生、熊本大山崎教授、産総研李先生）で集合写真を撮影しました。

2025.09.17

【学会】中野研究室のメンバーが日本金属学会2025年（第177回）春期講演大会（@北海道大学、9月17日～9月19日）に参加します。

〇小笹良輔、中野貴由：
[S5.28] [基調講演] L-PBFにより創製したBCC型Ti含有合金の急冷凝固組織

9月17日

〇重永徹平、松坂匡晃、松垣あいら、中野貴由：
[P127] PBF-LB法による高分子材料中の高次組織配向制御

〇山野大陸、山田夏子、松垣あいら、石本卓也、中野貴由：
[P129] ヒト頭蓋骨における階層的な異方性骨微細構造の解明

〇竹下恭平、中西陽平、松坂匡晃、松垣あいら、中野貴由：
[P312] 特異な直交性骨基質配向化制御機構の解明と生体組織配向性への影響

〇平田渉悟、小笹良輔、石本卓也、佐藤和久、今野晋也、石田清仁、中野貴由：
[P315] L-PBFによる炭化物析出強化型Co基超合金の微細組織制御と力学特性

〇内芝旭祥、小笹良輔、佐藤和久、中野貴由：
[P321] レーザ粉末床溶融結合を用いたTi準結晶の創製と組織解析

9月18日

〇松坂匡晃、田中謙次、大原秀真、松垣あいら、中野貴由：
¹⁵⁹ OCNの翻訳後修飾による耳小骨配向性制御と聴覚機能維持機構の解明

〇松垣あいら、渡邊稜太、中野貴由：
¹⁶⁰ 慢性炎症モデルにおける骨基質配向性変化と感染抵抗性への影響

〇宮澤啓太郎、小笹良輔、中野貴由：
[S5.30] レーザ粉末床溶融結合における窒素雰囲気ガスがTi-42Nb合金の微細組織と力学特性に及ぼす影響

9月19日

〇ゴクチェカヤオズカン、中野貴由：
¹⁸⁶ Hydrogen embrittlement behavior of Ni-based alloy fabricated by laser powder bed fusion

〇菊川泰地、石本卓也、眞山剛、中野貴由：
[S5.37] L-PBF を利用した Ni 基合金への人工界面構造導入による高強度化の体系的理解

〇星野壮希、石本卓也、Gokcekaya Ozkan、眞山剛、多根正和、中野貴由：
[S5.38] PBF-LB/Mを用いた形状・結晶方位制御によるNi基IN718の力学機能設計

2025.09.12

【報道】9月11日の産総研・中部大学・大阪大学・名古屋工業大学からのプレスリリースを受けて、多数の報道がなされました。

9月11日の産総研・中部大学・大阪大学・名古屋工業大学からのプレスリリースを受けて、多数の報道がなされました。

★日刊工業新聞
★Ｎｅｗｓウェーブ２１
★共同通信
★下野新聞
★沖縄タイムス+
★北海道新聞デジタル
★秋田魁新報社
★FM FUKUOKA
★山梨日日新聞デジタル

2025.09.11

【プレスリリース】Advanced Healthcare Materialsの研究論文掲載に関して、産総研・中部大・大阪大・名古屋工業大からプレスリリースがされました。

2025.09.09

【行事】毎年恒例の研究室旅行を行い大いに盛り上がりました。

9月8日、9日は中野研究室の毎年恒例行事である研究室旅行を実施しました。
今年はM1の学生が中心となって計画してくれ、観光やレクリエーションを通じて大いに盛り上がりました。

城崎温泉にて

天橋立にて

2025.09.06

【論文】Advanced Healthcare Materialsに、リン酸塩系バイオガラスの抗菌性と骨芽細胞応答に関する研究論文がOA論文として掲載されました。

Sungho Lee*, Hayato Asano, Makoto Sakurai, Takayoshi Nakano, and Toshihiro Kasuga:
Preparation of Bifunctional Orthosilicophosphate MgO-CaO-ZnO-P₂O₅-SiO₂ Glasses: in vitro Evaluation of Antibacterial Activity and Osteoblast Gene Expression Behavior, Advanced Healthcare Materials, (2025), article number e02546.

DOI: https://doi.org/10.1002/adhm.202502546

論文はこちら
PDFはこちら

Abstract
Phosphate and phosphate invert glasses contain various elements, with a wide range of compositions. Recently, our group reported orthosilicophosphate glasses (SPGs) and the glass network structure composed of orthophosphates and orthosilicates crosslinked by cations. ZnO is an intermediate oxide that improves the chemical durability of glass. Additionally, Zn²⁺ ions exhibit antibacterial activity and stimulate bone formation. In this work, ZnO-containing SPGs are prepared for biomedical applications. The glasses are mainly composed of PO₄, SiO₄, MgO₄, and ZnO₄ orthotetrahedral structures. The ZnO-containing SPGs exhibit excellent antibacterial activity, with bacterial counts > 5 orders of magnitude lower than that of the control. Meanwhile, ZnO-containing SPGs have mild inhibitory effects on cell proliferation by Zn²⁺ ions; however, they exhibit significant upregulation of osteogenic markers compared with the control owing to the release of inorganic ions from the glasses. The ZnO-containing SPGs prepared in this work exhibit bifunctional properties suitable for biomedical applications. They serve as bioadaptive materials capable of controlling gene expression by releasing therapeutic ions.

2025.09.05

第67回歯科基礎医学会学術大会で講演を行いました。

日本学術会議シンポジウム（市民公開講座）「マテリアルとライフの融合サイエンス」
「骨質再建のための材料表面/生物相界面反応理解とその人為的制御」
松垣あいら、中野貴由北九州国際会議場　A会場（メインホール）

写真：オーガナイザーの塙隆夫先生、松本卓也先生、樋田京子先生、石丸直澄先生、大矢根綾子先生とともに。

2025.09.01

【解説・論文】中野先生が特集したスマートプロセス学会誌「AM技術の進展と応用（Ⅱ）」が発行され、中野研関係の解説と論文が掲載されました。

中野先生が特集したスマートプロセス学会誌「AM技術の進展と応用（Ⅱ）」が発行され、中野研関係の解説と論文が掲載されました。
Vol. 14[No. 5]、2025（令和 7 年 9 月）、AM技術の進展と応用（Ⅱ）、スマートプロセス学会誌
【解説】
★桐原聡秀、中野貴由：巻頭「AM技術の進展と応用（Ⅱ）」、スマートプロセス学会誌、14[5], (2025), pp.199. ★小泉雄一郎、奥川将行、柳玉恒、中野貴由：新材料創製のための粉末床溶融結合式付加製造のデジタルツイン科学、スマートプロセス学会誌、14[5], (2025), pp.200-207.
★石本卓也、中野貴由：金属AMによる異方性機能設計―形状と結晶配向の重畳、スマートプロセス学会誌、14[5], (2025), pp.221-226.
★小笹良輔、Gokcekaya Ozkan、中野貴由：レーザ粉末床溶融結合によるBCC型ハイエントロピー合金のin-situ合金化、スマートプロセス学会誌、14[5], (2025), pp.243-248.
【研究論文】
★松坂匡晃、小坂朋生、山野大陸、船奥和真、劉甜、松垣あいら、中野貴由：生体用AMインプラント材料の抗菌特性評価のためのin vitro 共培養モデルの構築、スマートプロセス学会誌、14[5], (2025), pp.249-252.
★小笹良輔、Kim Yong Seong、朝倉光平、堀尾尚平、鰐渕良祐、中野貴由：金属3Dプリンタ用レーザ照射による非等量Ti-Nb-Mo-Ta-W系ハイエントロピー合金の組織形成挙動、スマートプロセス学会誌、14[5], (2025), pp.253-257.
★宮澤啓太郎、小笹良輔、内芝旭祥、清水佑太、中野貴由：L-PBF で造形した準安定β型Ti合金におけるヤング率の変化、スマートプロセス学会誌、14[5], (2025), pp.258-263.

2025.08.22

【論文】産総研や名工大との共同研究によるバイオガラスによるZnの徐放による骨質の向上に関する研究成果がAdvanced Healthcare Materialsに受理されました。9月9日に出版される予定です。

2025.08.06

【論文】Materials Today CommunicationsにTi合金の酸化抑制に関する中国東北大との共同研究論文が掲載されました。

Yiming Jin, Jiani Li, Takayoshi Nakano, Hideki Hosoda, Mitsuo Niinomi, Xiaowei Zhang, Deliang Zhang, Xiaoli Zhao*:
Zr-Enhanced Ambient-Air Thermal Oxidation of Ti-30Zr-5Mo Alloy Using Low Tβ for Implants, Materials Today Communications, (2025), Volume 48, 113442.

DOI: https://doi.org/10.1016/j.mtcomm.2025.113442

論文はこちら
PDFはこちら

Abstract
Metastable β-Ti alloy Ti-30Zr-5Mo (Tβ ≈ 700 °C) offers low modulus, biocompatibility, and strength for spinal rod implants but has limited hardness (280 Hv) and wear resistance. Conventional surface treatments like vacuum-based physical vapor deposition (PVD), are costly and complex. This study exploits the low Tβ and high Zr content (30 wt.%) of Ti-30Zr-5Mo alloy for single-step, ambient-air thermal oxidation at 600-700 °C, combining heat treatment with surface modification. The low Tβ ensures controlled oxidation, preventing over-oxidation, while Zr's selective oxidation forms a dense ZrO2-rich layer, which is harder than TiO2, enhancing surface hardness. Spontaneous tetragonal to monoclinic phase transitions in ZrO2 further improve toughness. The resulting 5 μm-thick oxide layers exhibit a threefold hardness increase (904 Hv vs. 280 Hv), a surface roughness of 0.30 μm (suitable for osseointegration), strong interfacial adhesion (critical load: 43 N), and an 18-fold reduction in corrosion current density (from 1.62×10-7 to 8.96×10-9 A·cm-2). Despite minor microcracks, the layers maintain structural integrity, offering exceptional durability. This atmosphere-free approach provides a scalable solution for orthopedic and dental implants, combining mechanical durability with biological integration. The insights into Zr-driven oxidation dynamics at low Tβ could inform vacuum-based processes, when controlled oxygen partial pressure might further optimize oxide layer properties, aligning with advancement in surface technology.

2025.08.01

2025年8月【解説】日本Additive Manufacturing学会誌のAMフュチャー「AMプロジェクト」（Vol. 1[No. 2]、2025（令和7年8月））が発行され、中野研関連解説が発行されました。

【解説】
日本Additive Manufacturing学会誌のAMフュチャー「AMプロジェクト」（Vol. 1[No. 2]、2025（令和7年8月））が発行され、中野研関連解説が発行されました。
Vol. 1[No. 2]、2025（令和7年8月）、AMフュチャー
★中野貴由、阿部英司、眞山剛、石本卓也：CREST ナノ力学―金属3Dプリンティングによるカスタム力学機能制御、 AMフュチャー、1[2]、(2025)、pp.191-194.
★小泉雄一郎、足立吉隆、森下浩平、佐藤和久、戸田佳明、石本卓也、木村禎一、中野貴由：超温度場材料創成学―AMを中心とした巨大ポテンシャル勾配による新材料創製、 AMフュチャー、1[2]、(2025)、pp.195-198. ★森浩亮、金孝鎮、中野貴由：炭素循環社会に貢献する金属AM触媒、 AMフュチャー、1[2]、(2025)、pp.219-222.

2025.07.29

【論文】Materials Today CommunicationsにTi合金の酸化抑制に関する中国東北大との共同研究論文が出版されました。

Yiming Jin, Jiani Li, Takayoshi Nakano, Hideki Hosoda, Mitsuo Niinomi, Xiaowei Zhang, Deliang Zhang, Xiaoli Zhao*:
Zr-Enhanced Ambient-Air Thermal Oxidation of Ti-30Zr-5Mo Alloy Using Low Tβ for Implants, Materials Today Communications, (2025), 113442.

DOI: https://doi.org/10.1016/j.mtcomm.2025.113442

論文はこちら

Abstract
Metastable β-Ti alloy Ti-30Zr-5Mo (Tβ ≈ 700 °C) offers low modulus, biocompatibility, and strength for spinal rod implants but has limited hardness (280 Hv) and wear resistance. Conventional surface treatments like vacuum-based physical vapor deposition (PVD), are costly and complex. This study exploits the low Tβ and high Zr content (30 wt.%) of Ti-30Zr-5Mo alloy for single-step, ambient-air thermal oxidation at 600-700 °C, combining heat treatment with surface modification. The low Tβ ensures controlled oxidation, preventing over-oxidation, while Zr's selective oxidation forms a dense ZrO2-rich layer, which is harder than TiO2, enhancing surface hardness. Spontaneous tetragonal to monoclinic phase transitions in ZrO2 further improve toughness. The resulting 5 μm-thick oxide layers exhibit a threefold hardness increase (904 Hv vs. 280 Hv), a surface roughness of 0.30 μm (suitable for osseointegration), strong interfacial adhesion (critical load: 43 N), and an 18-fold reduction in corrosion current density (from 1.62×10-7 to 8.96×10-9 A·cm-2). Despite minor microcracks, the layers maintain structural integrity, offering exceptional durability. This atmosphere-free approach provides a scalable solution for orthopedic and dental implants, combining mechanical durability with biological integration. The insights into Zr-driven oxidation dynamics at low Tβ could inform vacuum-based processes, when controlled oxygen partial pressure might further optimize oxide layer properties, aligning with advancement in surface technology.

Keywords
Ti-30Zr-5Mo alloy; Thermal oxidation; Oxidation mechanism; Internal oxidation; Surface modification

2025.07.28

【論文】Materials Today CommunicationsにTi合金の酸化抑制に関する中国東北大との共同研究論文が受理されました。

2025.07.02

【論文】バイオフィルムに関する研究が、Transactions of the IMF (YTIM)にOA論文として掲載されました。

Hideyuki Kanematsu*, Shochiku Kure, Risa Kawai, Hidekazu Miura, Takayoshi Nakano:
Antibiofilm Potential of Graphene-Dispersed Alkoxysilane Coatings:
A Materials Science Perspective, Transactions of the IMF (YTIM),
The International Journal of Surface Engineering and Coatings, (2025).
DOI: https://doi.org/10.1080/00202967.2025.2520667

論文はこちら
PDFはこちら

Abstract
This study investigates the antibiofilm properties of alkoxysilane-based coatings incorporating dispersed multilayer graphene powder. Graphene, synthesised via a proprietary method, was incorporated into a resin matrix at various concentrations (0.1%, 0.5%, and 1.0% by weight) and applied to glass substrates. Raman spectroscopy confirmed the presence of defect-rich, multilayer graphene, which is known to enhance antimicrobial surface properties. Biofilm formation by Staphylococcus epidermidis was evaluated using ISO 4768-standardised crystal violet staining. Results indicated that biofilm development was effectively suppressed at concentrations up to 0.5%, whereas an unexpected increase was observed at 1.0%, possibly due to graphene aggregation and reduced surface exposure. The findings suggest that both graphene concentration and dispersion quality critically influence antibiofilm efficacy. The study highlights the dual role of graphene, both as a physical and chemical antibacterial agent, and its potential application in medical, industrial, and hygienic materials. Further investigation is warranted to optimise dispersion and explore microbial-material interactions in real-world conditions.

Keywords
Graphene-dispersed coatings; alkosysilane resin; biofilm suppression; crystal violet assay; Raman spectroscopy

2025.07.01

2025年7月1日【解説・論文】中野先生が特集したスマートプロセス学会誌「AM技術の進展と応用（Ⅰ）」が発行され、中野研関係の解説と論文が掲載されました。

中野先生が特集したスマートプロセス学会誌「AM技術の進展と応用（Ⅰ）」が発行され、中野研関係の解説と論文が掲載されました。
Vol. 14[No. 4]、2025（令和7年7月）、AM技術の進展と応用（Ⅰ）、スマートプロセス学会誌
【解説】
★中野貴由、桐原聡秀：巻頭「AM技術の進展と応用（Ⅰ）」、スマートプロセス学会誌、14[4], (2025), pp.123. ★安田弘行、趙研、竹山雅夫、中野貴由：航空機エンジン用TiAlタービンブレードのAM、スマートプロセス学会誌、14[4], (2025), pp.175-180.
★森浩亮、金孝鎮、中野貴由、山下弘巳：AM 触媒反応管開発の最前線、スマートプロセス学会誌、14[4], (2025), pp.181-186.
【研究論文】
★熊谷祥希、髙橋茉莉、小柳禎彦、小笹良輔、中野貴由：レーザ粉末床溶融結合法の造形過程におけるFe基合金の変形挙動に及ぼすマルテンサイト変態の影響、スマートプロセス学会誌、14[4], (2025), pp.192-197.

2025.06.30

【学会】中野研究室のメンバーが THERMEC2025（@University of Tours, France, 6月30日～7月4日）に参加します。

2025/6/30
Invited Speaker
〇Design of high entropy alloy with suppressed elemental segregation for laser powder bed fusion process
Ozkan Gokcekaya, Yong Seong Kim, Takayoshi Nakano

Invited Speaker
〇Electron Microscopy Studies on Orientation-Controlled 316L Austenitic Stainless Steel
Produced by Laser Powder Bed Fusion
Kazuhisa Sato, Shunya Takagi, Satoshi Ichikawa, Takuya Ishimoto, Takayoshi Nakano

2025/7/1
Keynote Speaker
〇Innovative design of crystallographic textures and macroscopic shapes via metal additive manufacturing
Takayoshi Nakano

Poster presentation
〇Unique Hierarchical Structural Features Introduced by Laser Powder Bed Fusion and Their Contribution to Mechanical Function in IN718
Taichi Kikukawa, Takuya Ishimoto, Tsuyoshi Mayama, Ryosuke Ozasa, Takayoshi Nakano

Poster presentation
〇Microstructural Control of Unstable Beta-Type Titanium Alloy Through Powder Bed Fusion Using a Laser-Beam of Metals
Keitaro Miyasawa, Ryosuke Ozasa, Daisuke Egusa, Eiji Abe, Masakazu Tane, Takayoshi Nakano

Invited Speaker
〇Elastic properties of laser powder bed fusion processed β-phase Ti alloys
Masakazu Tane, Shota Higashino, Eisuke Miyoshi, Takuya Ishimoto, Takayoshi Nakano

Invited Speaker
〇Microstructure control of TiAl alloys using peculiar thermal history of additive manufacturing
Ken Cho, Hiroyuki Y. Yasuda, Masao Takeyama, Takayoshi Nakano

〇Novel cellular structure with phase-separation induced dislocation-network in Ti-Zr-Nb-Ta-Zr high entropy alloy fabricated by laser powder bed fusion
Daisuke Egusa, Han Chen, Ryosuke Ozasa, Masayuki Okugawa, Taisuke Sasaki, Takuya Ishimoto, Koizumi Yuichiro, Takayashi Nakano, Eiji Abe

Poster presentation
〇Spinodal Decomposition and Magnetic Properties of Single-Crystal-Like Fe-Cr-Co Alloy Fabricated by Laser-Powder Bed Fusion Type Additive Manufacturing
Takato Saito, Yuheng Liu, Masayuki Okugawa, Kazuhisa Sato, Takayoshi Nakano, Yuichiro Koizumi

2025/7/2
Invited Speaker
〇A Novel Strategy for the Control of Crystallographic Texture of Metals with Non-Cubic Crystal System via Powder Bed Fusion using a Laser-Beam of Metals
Ryosuke Ozasa, Koji Hagihara, Takayoshi Nakano

〇Discovery of nano-scaled promising strengthening factor in 316L stainless steel fabricated by laser
powder bed fusion
Fei Sun, Yoshitaka Adachi, Kazuhisa Sato, Takuya Ishimoto, Takayoshi Nakano, Yuichiro Koizumi

〇Nano-scaled solidification microstructure characteristics in additively manufactured 316L stainless steel
Fei Sun, Yoshitaka Adachi, Kazuhisa Sato, Takuya Ishimoto, Takayoshi Nakano, Yuichiro Koizumi

〇Influence of hierarchical structure on mechanical properties of additive manufactured IN718 alloys
Kippei Yamashita, Ken Cho, Hiroyuki Y. Yasuda, Takuma Saito, Taisuke Sasaki, Sawaizumi Katsuhiko, Masayuki Okugawa, Koizumi Yuichiro, Takayoshi Nakano

Invited Speaker
〇Growth of Antiphase Domain in Laser-Irradiated Region and Superelasticity of Single-Crystal Like Fe3Al Fabricated by Laser Powder Bed Fusion Process
Yuheng Liu, Tsubasa Sato, Masayuki Okugawa, Kazuhisa Sato, Hiroyuki Y. Yasuda, Takayoshi Nakano, Yuichiro Koizumi

2025/7/3
Invited Speaker
〇Additive Manufacturing of Cell-Based 3D Bone-Mimetic Collagen/Apatite Structures
Aira Matsugaki, Takayoshi Nakano

Invited Speaker
〇Control of Bone Microstructure Formation: Role of Soluble Proteins Secreted by Osteocytes
Tadaaki Matsuzaka, Aira Matsugaki, Takayoshi Nakano

2025.06.13

An international collaborative research project with Postec on a high-strength, high-ductility medium-high entropy alloy utilizing the competition between precipitation and lattice strain has been published in "Materials Science and Engineering A".

Jae Heung Lee, Hyeonseok Kwon*, Gang Hee Gu, Ji Yeong Lee, Sang Guk Jeong, Emad Maawad, Changwan Ha, Jaemin Wang, Byeong-Joo Lee, Sangbong Yi*, Takayoshi Nakano, Hyoung Seop Kim*:
Harnessing competitive interplay between precipitation and lattice distortion for strong and ductile medium-entropy alloy,
Materials Science and Engineering A, 942, (2025) 148642: 1-11.
DOI: https://doi.org/10.1016/j.msea.2025.148642

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Abstract
In Co-Cr-Fe-Ni-Mo-C ferrous medium-entropy alloys (FeMEAs), precipitation-driven alteration of matrix composition affects both the kinetics of deformation-induced martensitic transformation (DIMT) and the degree of lattice distortion. While DIMT has been well studied, the role of lattice distortion remains explored. In this study, we simultaneously enhance the strength and ductility in Co18Cr13Fe57.5Ni7.5Mo3C1 (at%) FeMEA by harnessing the competitive interplay between precipitation and lattice distortion. Two annealed samples with similar grain sizes but different precipitate characteristics were prepared. The sample with suppressed precipitation exhibits improved ductility while maintaining comparable strength. The two specimens exhibited similar yield strengths due to a trade-off between precipitation strengthening and solid solution strengthening. However, the sample with higher lattice distortion and reduced precipitation demonstrates superior strain-hardening behavior owing to the lattice distortion-induced back stress, acting as an effective strain-hardening mechanism, and delayed DIMT, serving as a ductilizing mechanism. This work offers a strategy to modulate strengthening and deformation mechanisms in Co-Cr-Fe-Ni-Mo-C FeMEAs via precipitation control.

2025.04.10

Research on improving the creep properties of Ti alloys has been published in Journal of Metallurgical and Materials Transactions A.

Prince Valentine Cobbinah*, Sae Matsunaga, Yoshiaki Toda, Ryosuke Ozasa, Takuya Ishimoto, Takayoshi Nakano, Tsutomu Ito, Yoko Yamabe-Mitarai:*
On the enhanced creep performance in Ti6246 achieved through Laser Powder Bed Fusion (LPBF) processing,
Metallurgical and Materials Transactions A, (2025), in press.
DOI: https://doi.org/10.1007/s11661-025-07759-8

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Abstract
The high susceptibility of the Ti-6Al-2Sn-4Zr-6Mo wt pct (Ti6246) alloy to microstructural changes stands as a challenge when processed by the laser powder bed fusion (LPBF) technology. However, leveraging the capabilities of the LPBF process to successfully control the microstructure (and/or crystallographic texture) of the Ti6246 could improve mechanical properties, particularly at elevated temperatures. In this study, the creep performance (at 500 °C) of Ti6246 fabricated from three different LPBF processing conditions and heat-treated (HT) at 885 °C were investigated. In the as-built state, all the LPBFed-Ti6246 exhibited columnar microstructures with crystallographic lamellar-like microstructure (CLM), a near-single crystal-like microstructure (SCM), and polycrystalline microstructure (PCM) textures, respectively. At low applied stresses (100-300 MPa), diffusional creep was the dominant deformation mechanism and its resistance depended on grain size. The reference β-forged-HT Ti6246, characterized by large equiaxed grains, exhibited the lowest strain rate compared to the columnar microstructure of SX1 (CLM)-HT, SX2 (SCM)-HT, and SX3 (PCM)-HT. Conversely, dislocation slip governed deformation at high applied stresses (400-580 MPa) and its efficacy depended on the α/β interfaces in the microstructures. Disjointed columnar grains in SX1 (CLM)-HT and the deformation of the polycrystalline grains in SX3 (PCM)-HT indicated that the melt pool boundaries were unstable in the LPBFed-Ti6246. SX2 (SCM)-HT exhibited the longest creep life due to the relatively stable melt pool boundaries and the near < 001 > SCM crystallographic texture parallel to the applied stresses. Shallow ductile dimples and tears and the observation of laser scan tracks characterized the fracture surfaces of the LPBFed-Ti6246. These indicated that failure occurred by intergranular ductile fracture resulting from the formation of microvoids at the melt pool boundaries.

2025.03.18

Research on computer simulation of AM has been published in Journal of the Japan Society of Powder and Powder Metallurgy.

Shuhei Mino, Masayuki Okugawa, Takayoshi Nakano, Yuichiro Koizumi:
Raking and Fusing Behaviors during Fabrication of Multiple-layers in Powder Bed Fusion: An integrated discrete Element and computational thermal fluid Dynamics Study
Journal of the Japan Society of Powder and Powder Metallurgy, 72, (2025), 16P-T6-11; S1465-S1469.
https://doi.org/10.2497/jjspm.16P-T6-11

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Abstract
In the powder bed fusion (PBF) type additive manufacturing (AM), understanding the relationship between the quality of the powder bed and the powder spreading process is crucial to avoiding defect formation. In this study, we investigated the powder-raking behavior during the multiple-layer fabrication process by discrete element method (DEM) and computational thermal-fluid dynamics (CtFD) simulations. The integrated PBF process simulation revealed that the gap height between the powder spreading blade and the build platform increases nonlinearly with the number of stacking layers, and accordingly, the powder-covered area ratio increases in the formed powder beds and affects the melt pool shapes. The powder raking behavior and melting and solidification behavior are related to each other, and both the powder raking and the irradiation conditions need to be optimized to obtain a high-quality part in the PBF process.

Keywords
additive manufacturing; powder bed fusion; discrete element method; computational thermal-fluid dynamics

2025.03.15

A paper on Young's modulus prediction for Ti alloys was published as an OA article in Additive Manufacturing (IF=10.3).

Shota Higashino, Daisuke Miyashita , Takuya Ishimoto, Eisuke Miyoshi, Takayoshi Nakano, Masakazu Tane*:
Low Young's modulus in laser powder bed fusion processed Ti-15Mo-5Zr-3Al alloys achieved by the control of crystallographic texture combined with the retention of low-stability bcc structure,
Additive Manufacturing, 102 (2025), 104720; 1-13.
https://doi.org/10.1016/j.addma.2025.104720

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Abstract
Metastable β (body-centered cubic)-phase Ti alloys, quenched from a high-temperature β-phase field, have attracted great interest as biomedical implants, owing to their low Young's modulus. Recently, the application of additive manufacturing (AM) to β-phase Ti alloys has gathered much attention, because the AM process can form anisotropic crystallographic texture in which an elastically soft direction is preferentially oriented, resulting in low Young's modulus in a specific direction. However, the effects of anisotropic texture and microstructure formed by the AM process on anisotropic elastic properties have not been clarified in detail. In the present study, we measured all the independent elastic stiffness components of β-phase Ti-15Mo-5Zr-3Al (mass%) alloys, prepared by bidirectional scanning with (XY-scan) and without (X-scan) an interlayer rotation of 90° in laser powder bed fusion (LPBF), one of the AM processes, using resonant ultrasound spectroscopy. The measurements revealed that the LPBF-processed Ti alloys exhibited strong elastic anisotropy and a low Young's modulus (below 60 GPa) in the <100>-oriented direction of the alloy prepared by the XY-scan. Furthermore, micromechanics calculations based on Eshelby's inclusion theory revealed that the single crystal constituting the alloys prepared by LPBF had almost the same elastic stiffness as that of a single crystal prepared by the floating zone melting, which indicated that the metastable β phase was retained by suppressing an easily occurring β- to ω-phase transformation during LPBF. These results indicate that texture control combined with retention of the metastable β phase by LPBF achieves biocompatible low Young's modulus.

Keywords
Laser powder bed fusion; Elastic properties; Titanium alloys; Crystallographic texture; ω phase transformation

2025.03.15

The one-process realization of alloying, microstructure control, and shape control by metal 3D printers was published in Materials & Design.

Yong Seong Kim, Ozkan Gokcekaya*, Kazuhisa Sato, Ryosuke Ozasa, Aira Matsugaki, Takayoshi Nakano*:
In-situ alloying of nonequiatomic TiNbMoTaW refractory bio-high entropy alloy via laser powder bed fusion: Achieving suppressed microsegregation and texture formation,
Materials & Design, 252, (2025), 113824; 1-18.
https://doi.org/10.1016/j.matdes.2025.113824

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Abstract
High-entropy alloys (HEAs) have attracted considerable attention owing to their excellent properties. However, the severe segregation of the constituent elements remains a common challenge in refractory HEAs. Recently, an approach to suppress segregation was proposed using laser powder bed fusion (LPBF) owing to the ultra-high cooling rates during solidification. Despite the advantages of LPBF, the persistent microsegregation between the dendritic and interdendritic regions of refractory HEAs and costly gas atomization process hinder the further development. To address these challenges, a novel nonequiatomic TiNbMoTaW refractory HEA was designed to minimize the difference between the liquidus and solidus temperatures to prevent segregation and phase separation for a better biological performance. In-situ alloying was implemented instead of costly and time-consuming gas atomization process. The segregation of constituent elements was suppressed by remelting, resulted in epitaxial growth and development of crystallographic texture, consequently reducing residual stress. The mechanical properties were improved due to the increase of solid solution strengthening and densification. It showed superior mechanical strength and equivalent biocompatibility compared to conventional biomaterials, indicating its superiority as a biomaterial. This study represents the first successful control of crystallographic texture through in-situ alloying of BioHEAs for next-generation biomaterials.

Keywords
High entropy alloys; Additive manufacturing; In-situ alloying; Crystallographic texture; Segregation

2025.03.14

The results of joint research on AM with Abe Lab. at the University of Tokyo were published in Additive Manufacturing (IF=10.3).

Han Chen, Daisuke Egusa*, Zehao Li, Taisuke Sasaki, Ryosuke Ozasa , Takuya Ishimoto, Masayuki Okugawa, Yuichiro Koizumi, Takayoshi Nakano, Eiji Abe*
Phase-separation induced dislocation-network cellular structures in Ti-Zr-Nb-Mo-Ta high-entropy alloy processed by laser powder bed fusion,
Additive manufacturing, 102, (2025), 104737; 1-14.
https://doi.org/10.1016/j.addma.2025.104737

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Abstract
Hierarchical structures, such as cellular structures, elemental segregations, and dislocation-network, are often proposed to enhance the mechanical properties of high-entropy alloys (HEAs) fabricated via additive manufacturing (AM). The formation of cellular structures is often attributed to elemental segregation during the solidification process or thermal strain resulting from the AM process. Here, we present a novel cellular structure where phase-separation and dislocation-network coupled in Ti-Zr-Nb-Mo-Ta HEA processed by laser powder bed fusion (L-PBF). Electron microscopy observations and X-ray diffraction (XRD) analyses show that this unique cellular structure consists of Zr-rich and Ta-rich body-center cubic (BCC) phases as the cell-wall and the cell-core, respectively, with their lattice constant difference of about 1 %. Moreover, a higher density of dislocations forming distinct networks is detected within this cellular structure, whose density reached 8 × 10 14 m 2 . Ma chine learning analysis reveals that the dislocations preferentially occur on the Zr-rich BCC side, thus accom modating the strains significant around the boundaries between the two BCC phases. With the aid of thermodynamic simulations, we propose a formation mechanism of the present cellular structure, which is governed by the elemental partitioning behavior of Zr and Ta during a solid-state phase separation under rapid cooling. Boundaries with this phase separation are introduced as semi-coherent interfaces with misfit disloca tions, introducing a high-density dislocation in the present material. This novel cellular structure can signifi cantly enhance the strength of AM HEAs, providing valuable insights for developing high-performance AM metals through the design of hierarchical microstructures.

Keywords
High-entropy alloy; Laser powder bed fusion; Cellular structure; Phase separation; Dislocation-network; Electron microscopy; Machine learning

2025.03.13

The Signature Pavilion "Future of Life" website has been renewed and reopened, and an article about Nakano Lab. has been posted on the "Future Technology" Seeds page.

An Innovative Bone Medical Device That Can Induce Strong Bones from the Early Stages of Regeneration

Click here to go to the top page→
https://expo2025future-of-life.com/
Click here to go to the Seeds of Future Technology top page→
https://expo2025future-of-life.com/about/future-technology-seeds/

2025.02.01

A paper on the microstructural effects of post-processing during laser and electron beam lithography has been published in the CIRP Journal of Manufacturing Science and Technology (IF=4.6).

Jibin Boban*, Afzaal Ahmed, Ozkan Gokcekaya , Takayoshi Nakano:
Ultra-precision surface treatment of beta-Titanium alloy printed using laser and electron beam melting sources, CIRP Journal of Manufacturing Science and Technology, 58, (2025), 01.006; 1-19.
https://doi.org/10.1016/j.cirpj.2025.01.006

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Abstract
Additive Manufacturing (AM) is a near net shape fabrication technology offering exceptional design freedom for complex part production. However, the inadequate surface quality and poorly generated micro-features adversely affect the functional performance of metal AM parts thereby restricting the direct adoption in biomedical implantation applications. Ultra-precision diamond turning (UPDT) can be regarded as a possible solution to overcome the aforementioned challenges in metal AM. However, the machinability of metal AM parts at ultra-precision level is highly sensitive to the material specific attributes and microstructure generated by the thermal characteristics of the process. In light of this, the present study follows a novel direction by investigating the dependence of distinct material characteristics imparted by two different AM powder melting sources on the ultra-precision post-treatment performance. Experiments were conducted on laser and electron beam printed beta-Ti alloy (Ti-15Mo-5Zr-3Al) which has potential importance in biomedical applications. The results demonstrate that the microstructural variations in respective samples affect the process performance and final surface integrity. The samples printed using laser powder bed fusion (LPBF) achieved a final surface finish (Sa) of ~66.3 nm after UPDT relative to the electron beam powder bed fusion (EPBF) samples (~104.3 nm). The cutting forces tends to exhibit sharp dip in forces in case of LPBF samples when micro-cutting was done perpendicular to the beam scanning direction. The chip morphology analysis corresponding to the LPBF and EPBF samples sub stantiates the generation of chips with segmentation/serrations on the free chip surface and parent material adhesion on the tool-chip contact surface. Further, precise microfeature generation was successfully accom plished on both the samples with minimal dimensional deviations on LPBF sample. Thus, the outcomes of the study establish the potential of UPDT in elevating the bioimplant surface standards of beta-Ti alloy with superior performance in LPBF samples.

Keywords
Additive manufacturing; Powder bed fusion; Diamond turning; Titanium; Microstructure