核融合発電所材料への新しいアプローチを印刷する(Printing a new approach to fusion power plant materials)

2023-10-17

2023-10-14 マサチューセッツ工科大学(MIT)

◆アーカンソー出身の大学院生アレクサンダー・オブライエンは、MITの核科学および工学部に入学し、核融合発電所用のセラミック-金属複合材料を3Dプリンティングで製造する研究を行っています。これらの材料は高温や放射線に耐える能力があり、将来の核融合発電所の建設に適しています。
◆オブライエンは、セラミックのナノ粒子を金属に埋め込むことで、高温での強度を向上させ、材料の寿命を延ばす方法を研究しています。これにより、核融合エネルギーの実現に向けた新たなアプローチが提供される可能性があります。

＜関連情報＞

ナノカーバイドとシリサイドのin-situ形成による付加製造インコネル718の強化 Strengthening additively manufactured Inconel 718 through in-situ formation of nanocarbides and silicides

Emre Tekoğlu, Alexander D. O’Brien, Jian Liu, Baoming Wang, Sina Kavak, Yong Zhang, So Yeon Kim, Shitong Wang, Duygu Ağaoğulları, Wen Chen, A. John Hart, Ju Li
Additive Manufacturing Available online: 2 March 2023
DOI:https://doi.org/10.1016/j.addma.2023.103478

Abstract

We report additive manufacturing (AM) of a nickel superalloy metallic matrix composite (Ni-MMC) using laser powder bed fusion (LPBF). Nanoceramic-containing composite powders were prepared by high-speed blender declustering and ball milling of as-received SiC nanowires (2 vol%) and Inconel 718 alloy powders, which produced a homogeneous decoration of SiC on the surfaces of Inconel particles. Analysis of the as-printed specimens revealed the dissolution of SiC nanowires during laser melting, leading to the in-situ formation of Nb- and Ti-based silicide and carbide nanoparticles. These in-situ formed nanoparticles resulted in a more desirable solidification microstructure of the AM Inconel 718 with fewer printing defects (cracks and pores) and slightly refined grain sizes. Mechanical characterization of the as-printed Ni-MMCs revealed notable increases in hardness, yield strength (by 16%), and ultimate tensile strength (σ_UTS, by 12%) compared to the reference samples without SiC addition. After heat treatment, the same composite samples displayed a 10% higher σ_UTS compared to identically treated unreinforced material while maintaining ∼14% total tensile elongation. We believe this in-situ precipitate formation presents a simple and effective method for strengthening additively manufactured high-temperature materials that could be used in the increasingly harsh environments in energy and propulsion applications.