【公開日：2024.07.25】【最終更新日：2024.05.29】
課題データ / Project Data
課題番号 / Project Issue Number
23UT0036
利用課題名 / Title
Cu/Nb multilayered fatigue
利用した実施機関 / Support Institute
東京大学 / Tokyo Univ.
機関外・機関内の利用 / External or Internal Use
内部利用（ARIM事業参画者以外）/Internal Use (by non ARIM members)
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）-
【重要技術領域 / Important Technology Area】（主 / Main）次世代ナノスケールマテリアル/Next-generation nanoscale materials（副 / Sub）-
キーワード / Keywords
EBSD,電子顕微鏡/ Electronic microscope,イオンミリング/ Ion milling
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
Briffod Fabien
所属名 / Affiliation
東京大学 大学院工学系研究科
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
利用形態 / Support Type
（主 / Main）機器利用/Equipment Utilization（副 / Sub）-
利用した主な設備 / Equipment Used in This Project
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
Multilayer metallic materials, composed of alternating layers of dissimilar metals spanning millimeter to nanometer thickness ranges, have gained significant popularity as a novel design approach in structural materials. The advent of severe plastic deformation processes, particularly accumulative roll bonding (ARB), has facilitated the fabrication of bulk nanolaminates, such as copper/niobium (Cu/Nb) nanolaminates, thus expanding their potential for use as structural materials. Extensive research employing experimental, theoretical, and numerical methods has been conducted to investigate the impact of the ARB process on Cu/Nb composites, encompassing layer thickness distribution, texture evolution, interfacial orientation relationships, and mechanical behavior. However, to ensure their suitability as structural materials, a comprehensive understanding of the deformation response and failure mechanisms under both monotonic and cyclic loading is imperative.
実験 / Experimental
The materials investigated were Cu/Nb laminates containing equal volume fraction of Cu and Nb and fabricated by ARB from pure Cu and Nb sheets. Different layer thicknesses laminates were produced. The microstructures were examined by means of electron backscattered diffraction (EBSD) measurements and synthetic microstructures were generated based on a previously developed framework. The microstructures were subjected to uniaxial tensile tests and four-point bending fatigue condition either along the rolling direction (RD) or transverse direction (TD) . The mechanical response was modeled by a rate-dependent. phenomenological crystal plasticity model and the local stress and strain distribution were investigated by Crystal Plasticity Finite Element Method.
結果と考察 / Results and Discussion
Three materials were successfully produced by ARB and investigated by EBSD as depicted in Fig. 1. . For the 250 layers
material, we observed recrystallized grains in Cu phase with the presence of
annealing twins. Each layer contains multiple grains not particularly elongated
along the rolling direction. On the other hand, the Nb phase already exhibit a
strong crystalloographic texture with very fine and elongated grains along the
rolling direction. With decreasing layer thickness, we see limited change in the IPF along
the rolling direction for the Nb phase while for the Cu phase each layer tends
to become single crystal through thickness with a high aspect ratio. For the
lowest thickness specimen, the crystal orientation of each layer tends to be
close to each other. Focusing on the Cu phase, the texture index significantly with the
decreased layer thickness as observed from the EBSD map. In the RD direction,
we observe a rotation from the [112] direction towards the [111] direction
while along the ND direction we not a rotation from about [120] direction
towards [112] leading to the {112}<111> interface for the Cu phase. In the case of the Nb phase, we observed limited changes
along the RD where the [011] direction orientation does not change while along
the ND we not a rotation from the [111] direction towards the [112] direction.
We then analyzed the tensile behavior of the materials along
the two directions RD and TD. We observed an increase in yield stress and tensile stress
with the decrease in layer thickness but we also note a lower ductility with
finer layer structures. This trend has been observed with many single-phase
nanocrystalline materials and is
attributed to the diminished work hardening capability of these materials. Similarly, the fatigue behavior was found to increase with the decrease in layer thicknesses.
図・表・数式 / Figures, Tables and Equations
Examples of EBSD maps of ARB Cu/Nb materials
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
This work was supported by JST SICORP Grant Number JPMJSC21E1, Japan. MHJ acknowledges support from A*STAR, Singapore (Grant No. A18B1b0061).
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
-
Fabien Briffod, Effect of Microstructure on the Tensile and Fatigue Behavior of an Accumulative Roll Bonded Cu/Nb Laminate Material, MATERIALS TRANSACTIONS, 65, 167-176(2024).
DOI: 10.2320/matertrans.MT-M2023081
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件