The microstructure and creep deformation of hot-pressed Si3N4 with different amounts of sintering additives

1996 ◽  
Vol 11 (1) ◽  
pp. 120-126 ◽  
Author(s):  
Sang-Young Yoon ◽  
Takashi Akatsu ◽  
Eiichi Yasuda
Keyword(s):  
Activation Energy ◽  
Silicon Nitride ◽  
Creep Rate ◽  
Grain Boundary ◽  
Apparent Activation Energy ◽  
Creep Test ◽  
Creep Deformation ◽  
Glassy Phase ◽  
Microstructural Observation ◽  
Rate Limiting

Compressive creep deformation of hot-pressed silicon nitride with different amounts of grain boundary glassy phase was investigated at 1300–1400 °C under 30–100 MPa. The stress exponent of the creep rate was determined to be nearly unity. The apparent activation energy of silicon nitride with a larger amount of glassy phase was measured to be about 700 kJ/mole, and that with a smaller amount of glassy phase was found to be 400 kJ/mole. In addition, the microstructural observation found that no cavity appeared and grain boundary glass was recrystallized during creep test. Thus, the rate-limiting steps in solution/precipitation creep mechanism change from the solution-reprecipitation of Si3N4 grains to the diffusion through the grain boundary with increasing the amount of glassy phase.

Creep Processes in MAR-M247 Nickel-Base Superalloy

2016 ◽  
Vol 258 ◽  
pp. 603-606
Author(s):  
Marie Kvapilová ◽  
Květa Kuchařová ◽  
Karel Hrbáček ◽  
Vàclav Sklenička
Keyword(s):  
Creep Deformation ◽  
Elevated Temperatures ◽  
Dislocation Creep ◽  
Nickel Base Superalloy ◽  
Deformation And Fracture ◽  
Creep Life Prediction ◽  
Controlling Mechanism ◽  
Nickel Base ◽  
Creep Regime ◽  
Base Superalloy

Creep processes in MAR-M247 Nickel - Base Superalloy were studied at elevated temperatures. The stress exponents of creep rate n and time to fracture m indicate power-low (dislocation) creep regime and suggest the same controlling mechanism for the creep deformation and fracture. The variation of values of parameter n within the interval of applied stress may indicate changes in the rate-controlling creep deformation mechanism. The possibility of using of Monkman-Grant relationship for creep life prediction was demonstrated.

Creep deformation and fracture behaviour of modified 9Cr-1Mo steel in flowing liquid sodium environment

2017 ◽  
Vol 702 ◽  
pp. 232-240 ◽  
Author(s):  
S. Ravi ◽  
J. Vanaja ◽  
V.D. Vijayanand ◽  
P. Rajasundaram ◽  
S. Vijayaraghavan ◽  
...  
Keyword(s):  
Creep Deformation ◽  
Fracture Behaviour ◽  
Liquid Sodium ◽  
Flowing Liquid ◽  
Deformation And Fracture

Microstructural Degradation Accompanying Tensile Creep Deformation in Quasi-Ductile Silicon Nitride

1999 ◽  
Vol 175-176 ◽  
pp. 321-334 ◽  
Author(s):  
František Lofaj ◽  
Atsushi Okada ◽  
Yasushi Ikeda ◽  
Y. Mizuta ◽  
Hatsuhiko Usami ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Creep Deformation ◽  
Tensile Creep ◽  
Microstructural Degradation

Interrelationship between Creep Deformation and Damage for Advanced Creep-Resistant Steels

2018 ◽  
Vol 774 ◽  
pp. 119-124
Author(s):  
Vàclav Sklenička ◽  
Květa Kuchařová ◽  
Marie Kvapilová ◽  
Luboš Kloc ◽  
Jiri Dvorak ◽  
...  
Keyword(s):  
Creep Deformation ◽  
Power Plants ◽  
Fracture Behaviour ◽  
Creep Data ◽  
Creep Life ◽  
Empirical Formulas ◽  
Deformation And Fracture ◽  
Creep Resistant Steels ◽  
Insight Into ◽  
Time Assessment

The components used in power plants generally operate at elevated and/or high temperature and are subjected to internal pressure. Under such conditions creep is of a great concern and there is an urgent demand for methods which can be used to predict the creep life. In this work, using our earlier published creep data for advanced creep-resistant T23 and P92 steels, the interrelationship between creep deformation and damage have been analysed by linking them to the identified acting mechanisms, in terms of empirical formulas for the fracture time assessment. The validity and the applicability of various formulas are examined with the objective to gain insight into the creep deformation and fracture behaviour of the steels under investigation.

3438 Creep deformation and fracture in clay reinforced nylon nanocomposite

2006 ◽  
Vol 2006.1 (0) ◽  
pp. 587-588
Author(s):  
Shijie ZHU ◽  
Masanori OKAZAKI ◽  
Arimitsu USUKI ◽  
Makoto KATOH
Keyword(s):  
Creep Deformation ◽  
Deformation And Fracture

Mechanical Properties in Small Dimensions

MRS Bulletin ◽  
2002 ◽  
Vol 27 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Richard P. Vinci ◽  
Shefford P. Baker
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Significant Role ◽  
Creep Deformation ◽  
Film Growth ◽  
Thin Film Growth ◽  
Length Scale ◽  
Deformation And Fracture ◽  
Anelastic Behavior

AbstractThis brief article describes the content of the January 2002 issue of MRS Bulletin focusing on Mechanical Properties in Small Dimensions. Articles discuss the current understanding ofstressevolution during thin-film growth, elastic and anelastic behavior, dislocation-mediated plasticity, creep deformation, and fracture. Emphasis is placed on explaining the mechanisms that underlie thewell-known fact that length scale can play a significant role in mechanical behavior.

Analysis of Internal Friction on Silicon Nitride with Visco-Elastic Model

2006 ◽  
Vol 317-318 ◽  
pp. 429-432 ◽  
Author(s):  
Shuji Sakaguchi
Keyword(s):  
Relaxation Time ◽  
Silicon Nitride ◽  
Internal Friction ◽  
Temperature Dependence ◽  
Creep Deformation ◽  
Maxwell Model ◽  
Elastic Model ◽  
Sintering Aids ◽  
Characteristic Peak ◽  
Nitride Ceramics

Temperature dependence of internal friction on silicon nitride ceramics with yttria and alumina sintering aids was discussed using 4-elements visco-elastic model. It is known that the internal friction of this ceramic material shows a characteristic peak at around 1040 oC and an exponential increase over 1200 oC. This temperature dependence of internal friction was well approximated with using parallel Maxwell model. The parameters for this model and the relaxation time on this model were obtained. The relaxation time was very short, compared to the transient creep deformation of this ceramics. The analyzed results on internal friction could not be related with the creep deformation.

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