Creep damage and interaction behavior of neighboring notches in components at elevated temperature

2021 ◽  
Vol 256 ◽  
pp. 107996
Author(s):  
Jian-Guo Gong ◽  
Sai-Sai Guo ◽  
Fu-Hai Gao ◽  
Tian-Ye Niu ◽  
Fu-Zhen Xuan
Keyword(s):  
Elevated Temperature ◽  
Creep Damage ◽  
Interaction Behavior

An Analysis of Elevated Temperature Fatigue and Creep Crack Growth

1976 ◽  
Vol 98 (4) ◽  
pp. 473-479 ◽  
Author(s):  
M. Do¨ner
Keyword(s):  
Elevated Temperature ◽  
Crack Growth ◽  
Growth Rates ◽  
Creep Crack Growth ◽  
Crack Tip ◽  
Creep Damage ◽  
Material Constant ◽  
Temperature Oxidation ◽  
Oxidation Damage ◽  
Crack Growth Rates

Existing crack growth laws which consider time and temperature effects are examined. Based on phenomenological observations, as well as mechanistic considerations, one of these laws is modified in order to provide an improved, universal elevated temperature crack growth law. It is assumed that there are essentially three processes through which crack growth rates are affected: decrease in strength and modulus with temperature, oxidation damage at the crack tip and creep damage at the crack tip. The rate controlling mechanism(s) which may be associated with each of these processes are discussed. The type of experiments which are needed for the determination of material constant(s) that describe the contribution from each process are outlined. The modified crack growth law, when applied to publish data on HS-188 alloy, results in a prediction of the crack growth rates within a factor of 2.5, in the temperature range of 873–1144 K and at cycle frequencies ranging from 0.01 to 10 Hz.

SIE ASME-NH Program for the Structural Integrity Evaluations of a LMR Subjected to Elevated Temperature Operations

2006 ◽  
Author(s):  
Gyeong-Hoi Koo ◽  
Jae-Han Lee
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Structural Integrity ◽  
Creep Damage ◽  
Pressure Vessels ◽  
Step Size ◽  
Time Step ◽  
Time Step Size ◽  
Ratcheting Strain ◽  
Creep Fatigue

In this paper, SIE ASME-NH (Structural Integrity Evaluation by ASME-NH) program, which has a computerized implementation of the details for ASME Pressure Vessels and Piping Code Section III Subsection NH rules including the time-dependent primary stress limits, total accumulated creep ratcheting strain limits, and the creep-fatigue limits for the reactor structures subjected to elevated temperature operations, are described with their detailed application procedures. Using this code, the selected high temperature structures which are subjected to two cycle types are evaluated and the sensitivity studies for the effects of the time step size, primary load, numbers of a cycle, normal temperature on the creep damage evaluations and the effects of the load history on the creep ratcheting strain calculations are investigated. From the selected applications, it is verified that the developed SIE ASME-NH Program is an easy user interface program and it can be an effective tool for the high temperature structural integrity evaluations of LMR.

Creep Damage of a Re/Ru-Containing Single Crystal Nickel-Based Superalloy at Elevated Temperature

2019 ◽  
Vol 795 ◽  
pp. 123-129
Author(s):  
Guo Qi Zhao ◽  
Su Gui Tian ◽  
Shun Ke Zhang ◽  
Ning Tian ◽  
Li Rong Liu
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Single Crystal ◽  
Deformation Mechanism ◽  
Creep Resistance ◽  
Creep Damage ◽  
Stress Axis ◽  
Dislocation Configuration ◽  
Nickel Based Superalloy ◽  
Damage And Fracture

By means of creep properties measurement, microstructure observation and contrast analysis of dislocation configuration, the creep behavior of a 4.5%Re/3.0%Ru-containing single crystal nickel-based superalloy at elevated temperature is investigated. Results show that the creep life of the alloy at 1040°C/160MPa is measured to be 725h to exhibit a better creep resistance at high temperature. In the primary stage of creep at high temperature, the γ phase in alloy has transformed into the N-type rafted structure along the direction vertical to the stress axis, the deformation mechanism of alloy during steady state creep is dislocations slipping in γ matrix and climbing over the rafted γ phase. In the latter period of creep, the deformation mechanism of alloy is dislocations slipping in γ matrix and shearing into the rafted γ phase. Wherein the dislocations shearing into the γ phase may cross-slip from {111} to {100} planes for forming the K-W locks to restrain the slipping and cross-slipping on {111} plane, which is thought to be the main reason of the alloy having a better creep resistance. As the creep goes on, the alternate slipping of dislocations results in the twisted of the rafted γ phase to promote the initiation and propagation of the cracks along the interfaces of γ/γ phase up to creep fracture, which is thought to be the damage and fracture mechanism of alloy during creep at high temperature.

Experimental Study on High Temperature Creep Damage of 1Cr5Mo Steel Based on Magnetic Parameters

2019 ◽  
Vol 795 ◽  
pp. 194-199
Author(s):  
Guang Xing Gao ◽  
Shan Shan Shao ◽  
Gong Tian Shen ◽  
Fa Kun Zhuang ◽  
Zhi Feng Li
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Engineering Application ◽  
Creep Damage ◽  
Optical Microscope ◽  
Measurement Technology ◽  
High Temperature Creep ◽  
Magnetic Parameters ◽  
Temperature Creep ◽  
Loop Measurement

Aiming at the evaluation of creep damage at elevated temperature of ferromagnetic materials in engineering application, the hysteresis loop measurement technology was adopted to study the creep damage behaviour of 1Cr5Mo steel. The creep testing at 600°C/90MPa of 1Cr5Mo steel were carried out to prepare specimens with various degrees of creep damage. The variation of magnetic parameter including coercivity (HC) and remanence (Br) with creep damage was analyzed. The microstructure evolution of 1Cr5Mo steel with different degrees of creep damage was observed by optical microscope. The results show that the coercivity and remanence show certain regularity with creep damage at elevated temperature. Moreover, the regularity is repeatable which indicates that the measurement technology based on magnetic parameters can be used for the evaluation of high temperature creep damage.

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