Synthesis of nano clusters and control of hardness and electrical conductivity of alloys by using energetic charged particles

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K12482
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 80040:Quantum beam science-related
• Research Institution: Osaka Metropolitan University (2022-2023); Osaka Prefecture University (2020-2021)
• Principal Investigator: Iwase Akihiro 大阪公立大学, 大学院工学研究科, 客員研究員 (60343919)
• Co-Investigator(Kenkyū-buntansha): 堀 史説 大阪公立大学, 大学院工学研究科, 准教授 (20275291)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 荷電粒子ビーム照射 / アルミ銅、銅チタン合金 / 硬度、導電率制御

Outline of Final Research Achievements

A large increase in the hardness of AlCu alloy was obtained in a short time by energetic ion irradiation at room temperature. Since the hardness did not change after irradiation at low temperatures, it was concluded that the hardness increase was due to the Cu nano-clusters produced by irradiation-enhanced diffusion of vacancies, which acted as obstacles against the dislocation motions. The Cu atom precipitation was confirmed by EXAFS measurements. In the case of CuTi alloy, the hardness and electrical conductivity increased by energetic electron irradiation. Analysis based on the particle-cutting mechanism explained the correlation between the hardness and conductivity increase. These experimental results demonstrate the superiority of charged particle irradiation for controlling the hardness and electrical conductivity of alloys at relatively low temperatures and in a short time as compared with conventional high-temperature aging treatments.

Free Research Field

材料工学

Academic Significance and Societal Importance of the Research Achievements

アルミ銅合金を軽量構造材・導電性材料として、また、銅チタン合金を電子デバイス基板、リードフレーム材料として実用に用いる場合、それらを高強度化、高導電率化することが求められる。本研究結果は、従来実施されてきた高温での熱処理に比べて、荷電粒子（イオン、電子）照射は、より低温でしかも短時間でこれら合金の強度、導電率を制御できることを示したものであり、材料プロセスの新たな方法としての荷電粒子照射法の可能性を示したことから、その社会的意義は大きい。また、照射促進偏析現象の基礎的過程に関する基礎的知見も得ることができているため、物質照射効果の基礎研究として、学術的意義も大きいと思われる。