High Temperature Fracture Toughness in Silicon Nitride and Sialon

1993 ◽  
Vol 115 (3) ◽  
pp. 268-272 ◽  
Author(s):  
Y. Mutoh ◽  
N. Miyahara ◽  
K. Yamaishi ◽  
T. Oikawa
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Transition Temperature ◽  
Silicon Nitride ◽  
Glass Phase ◽  
Temperature Transition ◽  
Brittle To Ductile Transition ◽  
Temperature Fracture ◽  
Increasing Temperature ◽  
Sintered Silicon

Fracture Toughness of HIP-sintered silicon nitride decreased with increasing temperature up to 1200°C. The brittle-to-ductile transition was observed in the temperature range from 1200°C to 1275°C: the fracture toughness rapidly increased in the transition region. Above the transition temperature, the fracture toughness decreased with increasing temperature. Fracture toughness of sialon increased with increasing temperature. Transition of fracture mechanism was observed in sialon around 1300°C. The differences of temperature dependence of fracture toughness between two materials are interpreted in terms of the effects of grain-boundary glass phase on fracture.

Viscoelastic Behavior of Segmented Elastomers

1967 ◽  
Vol 40 (4) ◽  
pp. 1105-1110 ◽  
Author(s):  
Stuart L. Cooper ◽  
Arthur V. Tobolsky
Keyword(s):  
Hydrogen Bonding ◽  
Glass Transition ◽  
High Temperature ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Viscoelastic Behavior ◽  
Temperature Transition ◽  
Hydrogen Bonding Interactions ◽  
Structural Nature ◽  
Hard Segments

Abstract Viscoelastic behavior of linear segmented elastomers was examined. The unusual properties found in spandex systems are also observable in hydrocarbon block co-polymers, indicating that hydrogen bonding interactions are perhaps not essential. Low temperature properties of segmented systems are governed by the structural nature of the associated flexible segments, which determines the value of the major glass transition temperature (Tg). It appears that an association of the hard segments provides a broad temperature range of enhanced rubbery modulus. This occurs between the major Tg and a secondary high temperature transition.

scholarly journals Evaluation of the Fracture Toughness on the Surface Layer in HIP-Sintered Silicon Nitride

2007 ◽  
Vol 1 (2) ◽  
pp. 181-190
Author(s):  
Tohru TAKAMATSU ◽  
Yoshio MIYOSHI ◽  
Hirotaka TANABE ◽  
Muneyoshi SEGAWA
Keyword(s):  
Fracture Toughness ◽  
Surface Layer ◽  
Silicon Nitride ◽  
Sintered Silicon

scholarly journals A New Method for Determining the Brittle-to-Ductile Transition Temperature of a TiAl Intermetallic

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1550
Author(s):  
Sarper Nizamoglu ◽  
Karl-Heinz Lang ◽  
Stefan Guth ◽  
Martin Heilmaier
Keyword(s):  
Transition Temperature ◽  
Charpy Impact ◽  
Plastic Strain Amplitude ◽  
Bending Tests ◽  
Brittle To Ductile Transition ◽  
Intermetallic Materials ◽  
Different Temperatures ◽  
Specific Temperature ◽  
Increasing Temperature ◽  
Fully Lamellar

Intermetallic materials typically change their deformation behavior from brittle to ductile at a certain temperature called the Brittle-to-Ductile Transition Temperature (BDTT). This specific temperature can be determined by the Charpy impact, tensile or bending tests conducted at different temperatures and strain rates, which usually requires a large number of specimens. In order to reduce the number of necessary specimens for finding the BDTT, a new methodology comprising cyclic loadings as the crucial step was studied on a fully lamellar TiAl alloy with composition Ti-48Al-2Nb-0.7Cr-0.3Si. The loading blocks are applied isothermally under strain control and repeated on the same specimen at different temperatures. The development of plastic strain amplitude with increasing temperature is analyzed to determine the BDTT of the specimen. The BDTTs found with the described method agree well with literature data derived with conventional methods. With the loading strategy presented in this study, the BDTT and additionally the effect of strain rate on it can be found by using a single specimen.

High temperature strength and fractography of sintered silicon nitride

1991 ◽  
Vol 17 (6) ◽  
pp. 335-341 ◽  
Author(s):  
A.K. Mukhopadhyay ◽  
S.K. Datta ◽  
D. Chakraborty
Keyword(s):  
High Temperature ◽  
Silicon Nitride ◽  
High Temperature Strength ◽  
Sintered Silicon

High-Temperature Fracture Mechanism of Low-Ca-Doped Silicon Nitride

1995 ◽  
Vol 78 (3) ◽  
pp. 673-679 ◽  
Author(s):  
Isao Tanaka ◽  
Ken'ichiro Igashira ◽  
Taira Okamoto ◽  
Koichi Niihara ◽  
Rowland M. Cannon
Keyword(s):  
High Temperature ◽  
Silicon Nitride ◽  
Fracture Mechanism ◽  
Doped Silicon ◽  
Temperature Fracture

The Room Temperature and Elevated Temperature Fracture Toughness Response of Alloy A-286

1978 ◽  
Vol 100 (2) ◽  
pp. 195-199 ◽  
Author(s):  
W. J. Mills
Keyword(s):  
Fracture Toughness ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Second Phase ◽  
Surface Micromorphology ◽  
Second Phase Particles ◽  
The Matrix ◽  
Temperature Fracture ◽  
Increasing Temperature ◽  
Base Superalloy

The elastic-plastic fracture toughness (JIc) response of precipitation strengthened Alloy A-286 has been evaluated by the multi-specimen R-curve technique at room temperature, 700 K (800°F) and 811 K (1000°F). The fracture toughness of this iron-base superalloy was found to decrease with increasing temperature. This phenomenon was attributed to a reduction in the materials’s strength and ductility at elevated temperatures. Electron fractographic examination revealed that the overall fracture surface micromorphology, a duplex dimple structure coupled with stringer troughs, was independent of test temperature. In addition, the fracture resistance of Alloy A-286 was found to be weakened by the presence of a nonuniform distribution of second phase particles throughout the matrix.

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