Investigation on deformation behavior of high entropy alloy single crystals

2015 Fiscal Year Final Research Report

• Project/Area Number: 26630348
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Structural/Functional materials
• Research Institution: Osaka University
• Principal Investigator: YASUDA Hiroyuki 大阪大学, 工学(系)研究科(研究院), 教授 (60294021)
• Co-Investigator(Kenkyū-buntansha): NAGASE Takeshi 大阪大学, 超高圧電子顕微鏡センター, 准教授 (50362661)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: ハイエントロピー合金 / 格子欠陥 / 構造・機能材料 / 転位

Outline of Final Research Achievements

Deformation behavior of CoCrFeNiAl0.3 and CoCrFeNiMn high entropy alloys with the fcc structure was examined using their single crystals and polycrystals. As a result, CoCrFeNiAl0.3 alloys were found to exhibit dynamic strain aging at high temperatures (600-800℃) associated with Al segregation on the dislocation core or stacking fault. Moreover, the dislocation structure is very planar due to the interaction between the dislocation and the L12-type nano-precipitates. It is also noted that grain refinement and the resultant strengthening can be easily realized in CoCrFeNiAl0.3 polycrystals by recrystallization after simple cold rolling. On the other hand, twinnning deformation in CoCrFeNiMn alloys depends on the stacking fault energy, average grain size and flow stress level.

Free Research Field

材料強度学