Nanostructural refinement of metal surface layer by using the accumulation of irreversible dislocation resulting from cyclic low-compressive loading

2015 Fiscal Year Final Research Report

• Project/Area Number: 26630001
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Materials/Mechanics of materials
• Research Institution: Hokkaido University
• Principal Investigator: Nakamura Takashi 北海道大学, 工学(系)研究科(研究院), 教授 (30237408)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: ナノ微細化 / 振動 / 雰囲気 / 非可逆転位

Outline of Final Research Achievements

This study developed a nanostructural refinement method of metal surface on the order of nm by using the accumulation of irreversible dislocation generated and moved resulting from low-compressive cyclic load. The refinement experiments were performed in air, nitrogen, Ar and vacuum and the effects of atmosphere, the amount of load, and the number of cycles applied were investigated. As a result of using low carbon steel and aluminum alloy for a test material, nanostrucrual layer with grain size on the order of 1 micrometer or below was formed in both alloys. The grain size and the depth of refined layer was able to be controlled by the compressive load and the number of cycles. The amount of refinement was superior in air and nitrogen; however it was not so much in argon. In vacuum, nanostructural layer could not be observed. The above findings revealed that this nanostructural refinement method requires the synergistic effect between atmosphere and dislocation.

Free Research Field

材料強度学