Mechanics of single crystal shape memory alloy structural elements

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K18825
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Mechanics of materials, Production engineering, Design engineering, and related fields
• Research Institution: Nagoya University (2018-2019); Kyoto University (2017)
• Principal Investigator: Araki Yoshikazu 名古屋大学, 環境学研究科, 教授 (50324653)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: 形状記憶合金 / 単結晶 / 超弾性 / 疲労 / 結晶方位 / 銅系合金

Outline of Final Research Achievements

We examined the fatigue and orientation dependence of mechanical properties in single crystal Cu-Al-Mn shape memory alloy bars. The conclusions can be summarized as follows. (1) The fatigue properties improved as the size of grain becomes larger. The single crystal bars had much superior fatigue to multiple (bamboo) crystal and poly crystal bars. (2) Strong orientation dependence was observed in plasticity and fracture properties in single crystal bars. Highly ductile response was observed when the orientation was close to <1 1 2>, <1 1 3>, or <0 0 1> direction. In these bars, the fracture strain was close to 100 %.

Free Research Field

材料力学

Academic Significance and Societal Importance of the Research Achievements

（１）これまで，単結晶大型部材の超弾性や塑性・破壊などの力学特性を調査した研究報告は見当たらない。そのため，結晶粒径と疲労特性の関係や，結晶方位と力学特性の異方性の関係を整理できれば，その新規性や学術的価値は高い。（２）単結晶Cu-Al-Mn形状記憶合金大型部材は，機械，航空，土木，建築など多くの分野で類例のない構造・機能部材として利用できる。そのため，部材の力学モデル構築に必要な力学特性を調査した本研究の結果は幅広い分野で利用でき，その波及効果は大きい。