Twinning-induced toughening forward hard and tough ceramics

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K15018
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 26020:Inorganic materials and properties-related
• Research Institution: The University of Tokyo
• Principal Investigator: Masuda Hiroshi 東京大学, 大学院工学系研究科(工学部), 講師 (20823701)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: セラミックス / 柔軟性 / フラッシュ焼結 / フラッシュ処理 / ジルコニア / TiO2 / 非弾性 / 粘弾性

Outline of Final Research Achievements

In the first part of this study, we conducted micromechanical testing of Y2O3-stabilized ZrO2 (YSZ) with nanotwin structures and successfully observed the twinning-induced toughening mechanism, wherein crack propagation was suppressed through twin domain nucleation and interface migration. In the latter part of the research, we discovered unexpected elastic softening behaviors among ceramics subjected to flash processing under strong electric fields and shifted our focus towards understanding this mechanism. The elastic softening behaviors were dependent on testing velocities and were observed in several oxide ceramics including 3YSZ, 8YSZ, and TiO2. These behaviors are possibly originated from anelasticity caused by recoverable motions of point defects introduced under strong electric fields.

Free Research Field

材料科学

Academic Significance and Societal Importance of the Research Achievements

本結果は、セラミックスの新たな機能創出につながる重要な成果だと考えられる。これまで材料の弾性率を制御することは困難だとされてきたが、強電場を利用するフラッシュ処理によって弾性特性を自在に操ることができれば、セラミックス部品の信頼性向上につながるさまざまな工学的応用につながる。例えば、セラミックスの弾性率を低下させることで柔軟性を付与する、あるいは金属などとの異種材料接合時に熱破壊への耐久性を高めることが可能となるなど、セラミックス部品の信頼性向上に貢献することが期待される。