High Temperature Static Fatigue Properties and Crack Healing Temperature of Crack Healed Mullite/SiC Composite Ceramics

2000 ◽  
Vol 2000 (0) ◽  
pp. 497-498
Author(s):  
Kiichi TSUJI ◽  
Kotokaze HURUSAWA ◽  
Tuyosi HANAGATA ◽  
Kotoji ANDO ◽  
Shigemi SATO
Keyword(s):  
High Temperature ◽  
Fatigue Properties ◽  
Static Fatigue ◽  
Crack Healing ◽  
Composite Ceramics ◽  
Healing Temperature

CRACK-HEALING BEHAVIOR AND BENDING STRENGTH OF Al2O3/SiC COMPOSITE CERAMICS ACCORDING TO THE AMOUNT OF ADDITIVE Y2O3

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2910-2915 ◽  
Author(s):  
KI WOO NAM
Keyword(s):  
High Temperature ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Composite Ceramic ◽  
Crack Healing ◽  
Composite Ceramics ◽  
Strength Recovery ◽  
In Situ Observations ◽  
Healing Temperature

Three Al 2 O 3/ SiC composite ceramics were prepared, which included 1, 3 or 5 wt. % Y 2 O 3, and their high-temperature bending strengths and in-situ crack-healing behaviors examined. A surface elliptical-crack of about 100 µm in diameter was introduces on the specimens using a Vickers hardness indenter. From in-situ observations, the Al 2 O 3/ SiC composite ceramic with 3 wt.% Y 2 O 3 showed superior crack-healing ability than the 1 and 5 wt.% Y 2 O 3 ceramics. The as-cracked specimen with 3 wt.% Y 2 O 3 showed strength recovery on healing for 1 hr at 1473 K in air, which may have been due to the lower crack-healing temperature on the addition of 3 wt.% Y 2 O 3. The heat-resistance limit temperatures of the crack-healed Al 2 O 3/ SiC composite ceramics were 1073, 1373 and 873 K for 1, 3 and 5 wt.% Y 2 O 3, respectively.

Crack healing behaviour and high-temperature strength of mullite/SiC composite ceramics

2002 ◽  
Vol 22 (8) ◽  
pp. 1313-1319 ◽  
Author(s):  
Kotoji Ando ◽  
Min-Cheol Chu ◽  
Kiichi Tsuji ◽  
Toshikazu Hirasawa ◽  
Yasuyoshi Kobayashi ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Strength ◽  
Crack Healing ◽  
Composite Ceramics

Strength Of Crack-healed Si_3N_4/SiC Composite Ceramics at Crack-healing Temperature

2000 ◽  
Vol 2000 (0) ◽  
pp. 499-500
Author(s):  
Sousuke SAKAMOTO ◽  
Sannshiro TAKESHITA ◽  
Kotoji ANDO ◽  
Min Cheol CHU ◽  
Shigemi SATO
Keyword(s):  
Crack Healing ◽  
Composite Ceramics ◽  
Healing Temperature

scholarly journals Crack Healing Behavior with Healing Temperature in Si3N4/SiC Composite Ceramics

2005 ◽  
Vol 15 (12) ◽  
pp. 780-785
Author(s):  
Oh-Sung Song ◽  
Kotoji Ando ◽  
Koji Takahashi ◽  
Wataru Nakao ◽  
Ji-Ho Ryu
Keyword(s):  
Crack Healing ◽  
Composite Ceramics ◽  
Healing Temperature

Crack-Healing under Cyclic Stress and Improvement of the Resultant Fatigue Strength of Si3N4/SiC

2006 ◽  
Vol 317-318 ◽  
pp. 453-456
Author(s):  
Koji Takahashi ◽  
Kotoji Ando ◽  
Shinji Saito
Keyword(s):  
Fatigue Strength ◽  
Bending Strength ◽  
Base Material ◽  
Cyclic Stress ◽  
Static Fatigue ◽  
Crack Healing ◽  
Protective Oxide ◽  
Healing Temperature ◽  
Cracked Specimens ◽  
Surface Length

Si3N4/SiC composite ceramics were hot-pressed in order to investigate their crack-healing behavior under cyclic stress and the resultant static fatigue strength. Semi-elliptical surface cracks of 100 μm in surface length were made on each specimen. The pre-cracked specimens were crack-healed under a cyclic bending stress of 210MPa in air at 900, 1000, 1100, and 1200 °C. The bending strength and static fatigue strength of the crack-healed specimens were systematically investigated at each healing temperature. The specimens which has been crack-healed and static fatigue-tested at 900 and 1000 °C showed lower static fatigue strength than those tested at 1100 and 1200 °C. Detailed investigation on the fracture surface of static fatigue-tested specimens showed that oxidation of the base material had strong effects on the static fatigue strength. It was found that when the specimens were pre-oxidized in air at 1300 °C, the surface was covered by a protective oxide layer, leading to a significant improvement of static fatigue strength at 900 and 1000 °C.

scholarly journals New Technology for Increasing Through-Life Reliability of Ceramics Components Using Self-Crack-Healing Ability

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Kotoji Ando ◽  
Koji Takahashi ◽  
Wataru Nakao ◽  
Toshio Osada ◽  
Kae Iwanaka
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
New Technology ◽  
Metallic Materials ◽  
Crack Healing ◽  
Structural Ceramics ◽  
Promising Technique ◽  
Component Reliability ◽  
Efficient Machine ◽  
Healing Temperature

Structural ceramics are superior to metallic materials in terms of their high-temperature strengths and critical heat proof temperatures. However, compared to metallic materials, ceramics exhibit lower fracture toughness, so they are more sensitive to flaws such as pores and cracks. The shortness considerably decreases the component reliability. To overcome the shortness, in this study, special attention is paid to structural ceramics with self-crack-healing ability. There are several advantages for using a material with self-crack-healing ability. (1) After an efficient machine operation, the materials are able to self-heal the cracks introduced by the machining. (2) The materials are able to self-heal the cracks introduced during service and recover the strength completely at healing temperature. However, ways of organizing the available knowledge to increase the through-life reliability of ceramics components have not been extensively studied. The authors propose a new concept and the corresponding flowchart. This new concept is a promising technique for increasing the through-life reliability of ceramics components with excellent self-crack-healing ability.

Strength and Surface Morphology of Si3N4 Composite Ceramics Coated with SiO2 Gel

2007 ◽  
Vol 124-126 ◽  
pp. 719-722 ◽  
Author(s):  
M.K. Kim ◽  
H.S. Kim ◽  
S.B. Kang ◽  
S.H. Ahn ◽  
Ki Woo Nam
Keyword(s):  
Test Specimen ◽  
Bending Strength ◽  
Crack Healing ◽  
Hot Press ◽  
Composite Ceramics ◽  
Coating Time ◽  
Healing Temperature ◽  
Cracked Specimens ◽  
Elliptical Cracks ◽  
Tensile Surface

The Si3N4/SiC and Si3N4/SiC/TiO2 composite ceramics were sintered at 1850 °C, for 2 h, in air by Hot-Press. A semi-elliptical surface crack was made at the center of the tensile surface of the test specimen using a Vickers indenter at a load of 24.5 N. By this method, the crack length on surface was made the semi-elliptical cracks of about 100 ㎛. Crack-healing behavior depends on healing temperature. The optimum healing condition of Si3N4/SiC and Si3N4/SiC/TiO2 composite ceramics are well known for 1,300 °C, 1h in air environment. So Smooth and as-cracked specimens were heated in this condition. To investigate temperature-dependence of the SiO2 gel coated specimen, four kinds of temperatures (800, 900, 1000, 1,300 °C) were tested. And to investigate SiO2 gel coating time-dependent, one and three times were coated. SiO2 gel coated specimens indicated increase of bending strength as the temperature goes up. Moreover the bending strength of SiO2 gel coating specimens was similar to the bending strength of healed smooth specimen at 900 °C.

K-0904 Strength of Si_3N_4/SiC Composite Ceramics at Crack Healing Temperature (1000℃)

2001 ◽  
Vol I.01.1 (0) ◽  
pp. 489-490
Author(s):  
Kotoji ANDO ◽  
Min-Cheol CHU ◽  
Keiji HOUJOU ◽  
Koji TAKAHASI ◽  
Shigemi SATO ◽  
...  
Keyword(s):  
Crack Healing ◽  
Composite Ceramics ◽  
Healing Temperature

scholarly journals Crack Healing and Mechanical Properties Recovery in SA 508–3 Steel

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 890 ◽  
Author(s):  
Yao Qiu ◽  
Ruishan Xin ◽  
Jianbin Luo ◽  
Qingxian Ma
Keyword(s):  
Mechanical Properties ◽  
Low Cycle Fatigue ◽  
Optical Microscope ◽  
Reduction Ratio ◽  
Fatigue Properties ◽  
Crack Healing ◽  
Hot Plastic Deformation ◽  
Crack Zone ◽  
Healing Temperature ◽  
The Impact

Internal cracks could be healed under the process of hot plastic deformation. In this study, mechanical properties recovery after crack healing in SA 508–3 steel were investigated. Microstructures of the crack healing zones were observed using an optical microscope (OM) and electron back scattered diffraction (EBSD) technology, and the recovery degrees of mechanical properties in the crack healing zones with the healing temperature and a reduction ratio were tested systematically. The results showed that the internal cracks in SA 508–3 steel disappeared and were replaced by newly formed grains, achieved by recrystallization and abnormal grain growth. The tensile properties of crack healing zones could be fully restored, while their impact and low cycle fatigue properties could only be partially achieved. The recovery degrees of mechanical properties in crack healing zones increased with increasing the healing temperature and reduction ratio in the temperature range of 950–1050 °C. When the temperature was above 1150 °C, the impact properties began to deteriorate because of grain coarsening and larger MA (martensite–austenite) constituents. The microstructural evolution of the crack zone in the SA 508–3 steel was sketched.

Sign in / Sign up

Export Citation Format

Share Document