Low-temperature deformability of brittle materials - New materials properties that can appear only for small volumes

2014 Fiscal Year Final Research Report

• Project/Area Number: 26630346
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Structural/Functional materials
• Research Institution: Kyoto University
• Principal Investigator: INUI HARUYUKI 京都大学, 工学(系)研究科(研究院), 教授 (30213135)
• Project Period (FY): 2014-04-01 – 2015-03-31
• Keywords: 協調的原子集団励起 / プラストン / マイクロピラー / 試験片サイズ依存性 / 臨界体積 / 転位 / 核生成 / 収縮転位

Outline of Final Research Achievements

Plastic deformation is observed by slip along the a-axis direction on basal planes even at room temperature when the specimen size is small of the order of micron meters in single crystals of 6H-SiC, in which high temperatures, at least 1000°C, are usually needed to induce plastic deformation in bulk specimens. In micropillar specimens, basal slip is observed to occur accompanied by a very high critical resolved shear stress (CRSS) above 5 GPa. Of significance to note is that these CRSS values do not depends much on specimen size up to sub-micron meters. Room temperature deformation was similarly observed in transition-metal silicides. These facts may indicate that (1) a deformation mechanism different from that observed in bulk at high temperatures can operate in micropillars at low temperatures and that (2) the observed CRSS values correspond to the nucleation stress for dislocations responsible for the new deformation mechanism.

Free Research Field

材料物性