Clarification of interfacial structure and fabrication of diamond dispersed Fe based alloy via friction stir densification processing

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K04742
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26030:Composite materials and interfaces-related
• Research Institution: Osaka Research Institute of Industrial Science and Technology
• Principal Investigator: Nagaoka Toru 地方独立行政法人大阪産業技術研究所, 森之宮センター, 主任研究員 (90416347)
• Co-Investigator(Kenkyū-buntansha): 水内 潔 地方独立行政法人大阪産業技術研究所, 森之宮センター, 研究フェロー (60416344)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: パルス通電焼結 / 摩擦攪拌プロセス

Outline of Final Research Achievements

Pulsed current sintering was performed on a mixture of Fe powder and copper-coated diamond powder. The friction stir processing could be performed with diamond particles at 5 wt% and 10 wt% content. The shape of the copper-coated diamond was not changed by the friction stir processing. A Cu layer with a thickness of 5 μm to 10 μm surrounded the diamonds, and no compound phases were observed at the interface. No defects or compound phases were observed at the interface between the Cu and Fe as well. The results of EBSD analysis showed that the grain size of the Fe matrix was 7.8 μm after sintering and 5.7 μm after the friction stir processing. The grain size has been refined by dynamic recrystallization during the friction stir processing.

Free Research Field

接合

Academic Significance and Societal Importance of the Research Achievements

ダイヤモンドは高い熱伝導率（2000 W/mK）を有するため、ダイヤモンド粒子分散Fe基合金を創製できれば、高い熱伝導率と優れた機械的性質を兼ね備えたFe基合金を作製することが可能となる。しかし、ダイヤモンドはFeと非常に反応し易く、特にA1変態点（約727℃）以上では、冷却過程でFe3C相が析出する。本研究成果により、パルス通電焼結とその後の摩擦攪拌プロセスを組み合わせ、A1変態点未満での焼結・緻密化を図ることで、ダイヤモンドとFeの反応を抑制したダイヤモンド粒子分散Fe基合金を作製することができた。