scholarly journals Grain Size Dependence of the Fracture Toughness of Silicon Nitride Ceramics

1991 ◽  
Vol 99 (1148) ◽  
pp. 320-323 ◽  
Author(s):  
Takeshi KAWASHIMA ◽  
Hiromi OKAMOTO ◽  
Hideharu YAMAMOTO ◽  
Akira KITAMURA
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Silicon Nitride ◽  
Size Dependence ◽  
Nitride Ceramics

Effect of α/β phase ratio on microstructure and mechanical properties of silicon nitride ceramics

2001 ◽  
Vol 16 (8) ◽  
pp. 2264-2270 ◽  
Author(s):  
Hirokazu Kawaoka ◽  
Tomohiko Adachi ◽  
Tohru Sekino ◽  
Yong-Ho Choa ◽  
Lian Gao ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Phase Ratio ◽  
Phase Content ◽  
Sintering Process ◽  
Β Phase ◽  
Nitride Ceramics ◽  
Pulse Electric ◽  
Sintering Condition ◽  
Sintered Materials

Highly densed silicon nitride ceramics with various α/β phase ratios were produced by pulse electric current sintering process. The β-phase content of Si3N4 in sintered materials varied from 20 to 100 wt% depending on the sintering condition. The microstructure was observed by scanning electron microscopy and investigated by image analysis. Young's modulus, hardness, fracture toughness, and strength were strongly dependent on the α/β phase ratio. The fracture toughness increased from 4.6 MPa m1/2 for 20-wt% b-phase content to 8.2 MPa m1/2 for 95-wt% β-phase content, and the fracture strength showed a maximum value of about 1.6 GPa at 60-to-80-wt% β-phase content.

Correlation between fracture toughness and microstructure of seeded silicon nitride ceramics

2007 ◽  
Vol 42 (18) ◽  
pp. 7920-7926 ◽  
Author(s):  
D. Bučevac ◽  
S. Bošković ◽  
B. Matović ◽  
Lj. Živković ◽  
M. Vlajić ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Nitride Ceramics

Novel Microstructures in Microwave Sintered Silicon Nitride

1996 ◽  
Vol 430 ◽  
Author(s):  
M. E. Brito ◽  
K. Hirao ◽  
M. Toriyama ◽  
M. Hirota
Keyword(s):  
Grain Size ◽  
Silicon Nitride ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Mechanical Performance ◽  
Microwave Sintering ◽  
Preliminary Results ◽  
Nitride Ceramics ◽  
Positive Effect ◽  
Sintered Silicon

AbstractPreliminary results on microwave sintering of seeded silicon nitride show that a well defined bi-modal grain size distribution is attainable in Si3N4-Y2O3-Al2O 3-MgO sintered bodies by microwave sintering at 28 GHz of materials seeded with ß-Si3N4 particles (2 vol. %). A positive effect on the mechanical performance is anticipated for these microstructurally controlled silicon nitride ceramics

Effects of Sintering Additives on the Microstructure and Mechanical Properties of Silicon Nitride Ceramics by GPS

2010 ◽  
Vol 105-106 ◽  
pp. 27-30 ◽  
Author(s):  
Wei Ru Zhang ◽  
Feng Sun ◽  
Ting Yan Tian ◽  
Xiang Hong Teng ◽  
Min Chao Ru ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Transformation ◽  
Silicon Nitride ◽  
Porous Silicon ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Additives ◽  
Microstructure And Mechanical Properties ◽  
Nitride Ceramics

Silicon nitride ceramics were prepared by gas pressure sintering (GPS) with different sintering additives, including La2O3, Sm2O3 and Al2O3. Effect of sintering additives on the phase-transformation, microstructure and mechanical properties of porous silicon nitride ceramics was investigated. The results show that the reaction of sintering additives each other and with SiO2 had key effects on the phase-transformation, grain growing and grain boundaries. With 9MPa N2 atmosphere pressure, holding 1h at 1850°C, adding 10wt% one of the La2O3, Sm2O3, Al2O3, porous silicon nitride was prepared and the relative density was 78%, 72%, 85% respectively. The flexural strength was less than 500MPa, and the fracture toughness was less than 4.8MPam1/2. Dropping compounds sintering additives, such as La2O3+Al2O3, Sm2O3+Al2O3 effectively improves the sintering and mechanical properties. The relative density was 99.2% and 98.7% with 10wt% compounds sintering additives. The grain ratio of length to diameter was up to 1:8. The flexural strength was more than 900MPa, and the fracture toughness was more than 8.9MPam1/2.

scholarly journals Grain Size Dependence of Fracture Toughness in an Ultrahigh Strength Maraging Steel

1983 ◽  
Vol 69 (1) ◽  
pp. 145-152 ◽  
Author(s):  
Yoshikuni KAWABE ◽  
Seiichi MUNEKI ◽  
Junji TAKAHASHI
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Maraging Steel ◽  
Size Dependence ◽  
Ultrahigh Strength
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