Strengthening by stress oriented precipitates in Aluminium alloy micro piller and dislocation dynamics simulation

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K05164
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: MURAISHI Shinji 東京工業大学, 物質理工学院, 准教授 (70345156)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: アルミニウム合金 / マイクロメカニクス / 時効析出 / 応力時効 / 転位動力学

Outline of Final Research Achievements

By applying stress aging method, stress orienting effect of precipitates and its mechanical properties of age-hardenable aluminum alloys were clarified.
By analyzing the internal stress of misfit precipitates using the Eshelby inclusion method, it was shown that the geometric arrangement of precipitation variants affects the interaction force on the dislocation motion, resulting in the emergence of mechanical anisotropy. The internal stress caused by precipitates was also investigated in case of that the plastic deformation is dominant in matrix phase.By analyzing dislocation motion in an internal stress field using the discrete dislocation dynamics method, it was found that the elementary process of dislocation motion was greatly affected by the distribution of local internal stress, and as a result, the relationship between the external force and plastic strain when a dislocation overcomes a precipitate was clarified.

Free Research Field

金属工学，力学特性，転位論

Academic Significance and Societal Importance of the Research Achievements

軽量で比強度に優れた析出強化型アルミニウム合金は，輸送機器の燃費向上に不可欠な社会基盤材料である。より優れた材料強度を得る為には，主たる強化機構である微細な析出分散物による析出強化の材料設計の原理原則を明らかとする必要がある。ミスフィット析出物を特定の結晶面に配列制御した材料では，材料強度に力学的な異方性が生じることを実験的に明らかとし，析出形状と方位による析出強化量の違いを理論的に示した。