An Abnormal Increase of Fatigue Life with Dwell Time during Creep-Fatigue Deformation for Directionally Solidified Ni-Based Superalloy DZ445

2018 ◽  
Vol 37 (3) ◽  
pp. 277-284 ◽  
Author(s):  
Biao Ding ◽  
Weili Ren ◽  
Kang Deng ◽  
Haitao Li ◽  
Yongchun Liang
Keyword(s):  
Fatigue Life ◽  
Hysteresis Loop ◽  
Dwell Time ◽  
Fatigue Behavior ◽  
Maximum Energy ◽  
Abnormal Behavior ◽  
Directionally Solidified ◽  
Creep Fatigue ◽  
Abnormal Increase ◽  
Fatigue Deformation

AbstractThe paper investigated the creep-fatigue behavior for directionally solidified nickel-based superalloy DZ445 at 900 °C. It is found that the fatigue life shows an abnormal increase when the dwell time exceeds a critical value during creep-fatigue deformation. The area of hysteresis loop and fractograph explain the phenomenon quite well. The shortest life corresponds to the maximal area of hysteresis loop, i. e. the maximum energy to be consumed during the creep-fatigue cycle. The fractographic observation of failed samples further supports the abnormal behavior of fatigue life.

The Influence of Dwell Time on Low Cycle Fatigue Behavior of Ni-base Superalloy IC10

2017 ◽  
Vol 36 (8) ◽  
pp. 795-803
Author(s):  
Anqiang Wang ◽  
Lu Liu ◽  
Zhixun Wen ◽  
Zhenwei Li ◽  
Zhufeng Yue
Keyword(s):  
Fatigue Life ◽  
Dwell Time ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Dislocation Line ◽  
Reverse Direction ◽  
Structure Evolution ◽  
Cycle Fatigue ◽  
Creep Fatigue ◽  
Base Superalloy

AbstractLow cycle fatigue and creep-fatigue experiments of IC10 Ni-base superalloy plate specimens with multiple holes were performed below 1,000 °C. The average fatigue life is 105.4 cycles, while the creep-fatigue life is 103.4 cycles, which shows that the life of creep-fatigue is reduced 1–2 times compared with low cycle fatigue life. After tests, the detailed fracture and microscopic structure evolution were observed by scanning electron microscopy (SEM); meanwhile, the constitutive model based on crystal plasticity theory was established and the fracture mechanism was analyzed. Three conclusions have been obtained: First, the load during dwell time leads to the damage accumulation caused by deformation and the interaction of fatigue and creep shortens the service life of materials seriously. Second, in order to maintain the macroscopic deformation, a new slip plane starts to makes the dislocation slide in reverse direction, which leads to fatigue damage and initial cracks. Third, the inner free surface creates opportunities for escape of the dislocation line, which is caused by the cavity. What’s more, the cure dislocation generated by cyclic loading contributes to the formation and growth of cavities.

Revealing the creep-fatigue deformation mechanism for a directionally-solidified Ni-based superalloy DZ445 at 900 °C

2018 ◽  
Vol 5 (7) ◽  
pp. 076513 ◽  
Author(s):  
Biao Ding ◽  
Weili Ren ◽  
Jianchao Peng ◽  
Yunbo Zhong ◽  
Fei Li ◽  
...  
Keyword(s):  
Deformation Mechanism ◽  
Directionally Solidified ◽  
Creep Fatigue ◽  
Fatigue Deformation

Effect of Surface Recrystallization on the Low Cycle Fatigue Behavior of Directionally Solidified Superalloy DZ4 by In Situ SEM Studies

2012 ◽  
Vol 706-709 ◽  
pp. 2456-2461
Author(s):  
Xian Feng Ma ◽  
Hui Ji Shi
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Shot Peening ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Directionally Solidified ◽  
Annealing Heat Treatment ◽  
Crack Growth Rates

The effect of recrystallization on the low cycle fatigue life of DZ4 directionally solidified superalloy was investigated for specimens with three different recrystallized layers, which were generated by shot peening (0.1MPa, 0.3MPa and 0.5MPa respectively) and a subsequent annealing heat treatment. The fatigue life showed a decrease for recrystallized specimens with shot-peening of 0.1 MPa and 0.3 MPa, and an unusual increase for that of 0.5MPa, in comparison with the original DZ4 specimen. In-situ SEM observations were performed on the short crack growth behaviors for both original and recrystallized specimens, which revealed the fracture mechanism and the interaction with microstructure. Quantitative analysis of fatigue crack growth rates rationalized the influence of recrystallization on the low-cycle fatigue life of DZ4.

Effect of dwell time on creep-fatigue life of a high-Nb TiAl alloy at 750°C

2015 ◽  
Vol 109 ◽  
pp. 61-63 ◽  
Author(s):  
Long Yu ◽  
Xiping Song ◽  
Li You ◽  
Zehui Jiao ◽  
Huichen Yu
Keyword(s):  
Fatigue Life ◽  
Dwell Time ◽  
Tial Alloy ◽  
Creep Fatigue

Evaluation of Creep-Fatigue Life Using Backscattering of Rayleigh Surface Wave

2005 ◽  
Vol 297-300 ◽  
pp. 415-420 ◽  
Author(s):  
Byeong Soo Lim ◽  
Bum Joon Kim ◽  
Sung Jin Song ◽  
Young H. Kim
Keyword(s):  
Fatigue Life ◽  
Surface Wave ◽  
Fatigue Damage ◽  
Power Plants ◽  
Fatigue Behavior ◽  
Hold Time ◽  
Rayleigh Surface Wave ◽  
P92 Steel ◽  
Creep Fatigue ◽  
Main Steam

The application of nondestructive evaluation to creep-fatigue damage was examined in this paper. Generally, as the hold time of static load increases, the degradation of material becomes more rapid and the creep-fatigue life decreases. Therefore, in the evaluation of creep-fatigue strength and life of high-pressure vessel such as main steam pipe at high temperature is very important in power plants. In this study, the creep-fatigue behavior of P92 steel was evaluated nondestructively by the backscattered ultrasound using the creep-fatigue specimens. The results obtained by Rayleigh surface wave of backscattered ultrasound were compared and analyzed with the experimental parameters. Also, the relation between the SDA (slope of degraded area) and creep-fatigue life was examined. From the result of nondestructive test, we suggest that SDA would be used as the new parameter for the evaluation of creep-fatigue damage. As the degradation increased, the SDA decreased and also the creep-fatigue life decreased.

scholarly journals Creep-fatigue interaction in heat resistant austenitic alloys

2018 ◽  
Vol 165 ◽  
pp. 05001 ◽  
Author(s):  
Hugo Wärner ◽  
Mattias Calmunger ◽  
Guocai Chai ◽  
Johan Moverare
Keyword(s):  
Fatigue Life ◽  
Dwell Time ◽  
Mechanical Test ◽  
Testing Temperature ◽  
Austenitic Steels ◽  
Maximum Strain ◽  
Specific Test ◽  
Austenitic Alloys ◽  
Creep Fatigue ◽  
The Given

This work includes an investigation of two commercial austenitic steels: UNS S21500 (Esshete 1250) and UNS S31035 (Sandvik SanicroTM 25). The materials were exposed to isothermal strain controlled fatigue with load controlled dwell time at maximum strain. The testing temperature used was 700°C and the test cycles were performed in tension. Mechanical test data were obtained and analysed in order to define creep-fatigue damage diagrams at failure for the investigated austenitic alloys. During the given conditions, Sanicro 25 showed superior creep-fatigue life, suffered less amount of creep elongation for the same amount of strain amplitude and dwell times compared to Esshete 1250. Both alloys showed creep-fatigue interaction damage for specific test configurations.

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