BRITTLENESS,TOUGHNESS AND DUCTILITY OF CERAMICS -THE MICROSCOPIC PROCESSES AND CHARACTERIZATION.
Grant-in-Aid for Scientific Research (A)
Inorganic materials/Physical properties
|Research Institution||TOYOHASHI UNIVERSITY OF TECHNOLOGY|
SAKAI Mototsugu TOYOHASHI UNIVERSITY OF TECHNOLOGY,FUCULTY OF ENGINEERING,PROFESSOR, 工学部, 教授 (50124730)
菅沼 幹裕 愛知県工業技術センター, 材料部, 主任研究員
PEZZOTTI G. 豊橋技術科学大学, 工学部, 助手 (70262962)
SUGANUMA Motohiro AICHI INDUSTRIAL RESEARCH INSTITUTE,SENIOR RESEARCHER
|Project Fiscal Year
1995 – 1996
Completed(Fiscal Year 1996)
|Budget Amount *help
¥12,500,000 (Direct Cost : ¥12,500,000)
Fiscal Year 1996 : ¥3,700,000 (Direct Cost : ¥3,700,000)
Fiscal Year 1995 : ¥8,800,000 (Direct Cost : ¥8,800,000)
|Keywords||CERAMICS / BRITTLENESS / TOUGHNESS / DOUCTILIGY / CHARACTERIZATION,ANALYSIS / セラミックス / 脆性 / 靭性 / 延性 / 評価・解析 / 靱性 / 圧子力学 / 高温変形 / クリープ / 応力緩和|
1) The brittleness and the ductility as characteristic material parameters were defind and derived based on an energry principle of indentation contact mechanics. The brittleness/ductility parameter gives a quantitative measure for characterizing the machinability of brittle materials.
2) An apparatus was designed for characterizing the brittleness/ductility parameter and the degree of indentation-induced damage in a wide range of temperatures ranging from room temperature to 1,400ﾟC.
3) Conducted were the theoretical consideration and experimental work of viscoelatic indentation contact deformation of brittle materials at elevated temperatures. The indentation hysteresis energy was successfully utilized to characterize the viscoelastic behavior of surface deformation.
4) An acoustic microscopy was applied to the surface damage introduced by indentation contact. An analytical method for characterizing the damage evolution has been established.
5) A nonlinear rheological constitutive equati
on was proposed based on considerations of the grain-boundary sliding and grain interlocking of polycrystalline ceramics with grain-boundary melt at elevated temperatures.
6) An experimental apparatus was designed for examining viscoelastic behavior of polycrystalline materials at elevated temperatures up to 1600ﾟC.A novel test specimen geometry (double shear geometry) under compressive loading mode makes possible to conduct rheological testing under simple shear deformation. An experimental scrutiny confirmed that the constituteve equation proposed in Item 5) quantitatively predicts the nonlinear viscoelastic behavior associated with grain-boundary sliding and grain interlocking.
7) Toughening processes and mechanisms have been examined via experimental as well as theoretical studies on the mixed-mode fracture and R-curve behavior of several types of ceramics. A novel test technique and a fracture mechanics-based size-effect law were proposed to estimate process zone/wake zone sizes.
Research Output (19results)