High-Cycle Fatigue Behavior and Damage Mechanism of Multiphase Al-Si Piston Alloy at Room and Elevated Temperatures

2018 ◽  
Vol 20 (6) ◽  
pp. 1700972 ◽  
Author(s):  
Haiquan Liu ◽  
Jianchao Pang ◽  
Meng Wang ◽  
Shouxin Li ◽  
Zhefeng Zhang
Keyword(s):  
High Cycle Fatigue ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Damage Mechanism ◽  
Cycle Fatigue ◽  
Piston Alloy

High cycle fatigue behavior of a single crystal superalloy at elevated temperatures

2007 ◽  
Vol 454-455 ◽  
pp. 357-366 ◽  
Author(s):  
Y. Liu ◽  
J.J. Yu ◽  
Y. Xu ◽  
X.F. Sun ◽  
H.R. Guan ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Cycle Fatigue ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Single Crystal Superalloy ◽  
Cycle Fatigue

Elucidation of the High Cycle Fatigue Damage Mechanism of Modified 9Cr-1Mo Steel at Elevated Temperature

2015 ◽  
Author(s):  
Takuya Murakoshi ◽  
Motoyuki Ochi ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Elevated Temperatures ◽  
Surface Hardness ◽  
Diffraction Method ◽  
Fatigue Loading ◽  
Damage Mechanism ◽  
Fatigue Tests ◽  
Electron Back Scatter Diffraction ◽  
Cycle Fatigue

Modified 9Cr-1Mo steel is one of the heat-resistant steels developed for steam generator in a FBR (Fast Breeder Reactor). When it is used in a FBR, the lifetime of the steel under HCF (High Cycle Fatigue) and V-HCF (Very-High Cycle Fatigue) caused by flow-induced vibration has to be considered for assuring its long-term reliability up to 1011 cycles. Since previous studies showed that the fatigue limit did not appear up to 108 cycles, it is necessary to investigate the fatigue strength of this alloy in cycles higher than 108 cycles. In this study, in order to clarify high cycle fatigue strength and fracture mechanism of the modified 9Cr-1Mo steel, the change of the lath martensitic strengthening structure was observed in detail on the surface of specimens fractured by rotary bending fatigue tests by using EBSD (Electron Back-Scatter Diffraction) method. The Kernel Average Misorientation (KAM) value obtained from the EBSD analysis was used for the quantitative evaluation of the change of the lath martensitic texture. It was found that the average KAM values clearly decreased on the surface areas of the fractured specimens after the application of 107-108 cycles of fatigue loading at temperatures higher than 550°C. This result indicates that degradation of the lath martensitic texture occurred around the surface of specimens tested at the temperature higher than 550°C. In order to quantitatively evaluate the decrease of its strength, a hardness test was performed at room temperature by using a nanoindentation method. It was confirmed that the surface hardness of specimens decreased drastically in the specimens fractured at temperatures higher than 550°C. From these results, it was concluded that the effective 0.2%-proof stress decreased during the fatigue tests by the degradation of the lath martensitic texture caused by the fatigue loading at elevated temperatures. Further analyses are indispensable for explicating the damage mechanism more in detail.

Effect of stress ratio and mean stress on high cycle fatigue behavior of the superalloy IN718 at elevated temperatures

2019 ◽  
Vol 6 (9) ◽  
pp. 0965a6 ◽  
Author(s):  
Dhananjay Pradhan ◽  
G S Mahobia ◽  
K Chattopadhyay ◽  
D C Fernando ◽  
N Paulose ◽  
...  
Keyword(s):  
Stress Ratio ◽  
High Cycle Fatigue ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Mean Stress ◽  
Cycle Fatigue

Temperature Dependence of High-Cycle Fatigue Behavior of a Ni-Base Single Crystal Superalloy

2007 ◽  
Vol 546-549 ◽  
pp. 1219-1224 ◽  
Author(s):  
Y. Liu ◽  
Jin Jiang Yu ◽  
Yan Xu ◽  
Xiao Feng Sun ◽  
Heng Rong Guan ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Cycle Fatigue ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Testing Temperature ◽  
Cycle Fatigue ◽  
Air Atmosphere ◽  
Ultimate Failure ◽  
Increasing Temperature

Smooth specimens of single crystal (SC) superalloy SRR99 with [001] orientation were subjected to high-cycle fatigue (HCF) loading at temperatures of 700°C, 760°C, 850°C and 900°C in air atmosphere. The results demonstrated that conditional fatigue strength reached the maximum at 760°C and decreases with increasing temperature. Analysis on fracture surface showed a trend for cleavage rupture at 850°C and 900°C and ductile rupture at 700°C and 760°C. Fatigue cracks initiated at the surface or subsurface were primarily responsible for the ultimate failure. The influence of testing temperature on fatigue lifetime was studied by examining evolution of the microstructure through SEM observation. With the process of cyclic loading at elevated temperatures, the primary cuboidal γ′ precipitates tended to agglomerate and spheroidized, meanwhile a larger number of secondary γ′ particles were formed in the γ matrix in specimens fatigue tested at 700°C, which would have a significant effect on the high temperature properties.

High Cycle Fatigue Properties of Modified 9Cr-1Mo Steel at Elevated Temperatures

2012 ◽  
Author(s):  
Yoshiaki Matsumori ◽  
Jumpei Nemoto ◽  
Yuji Ichikawa ◽  
Isamu Nonaka ◽  
Hideo Miura
Keyword(s):  
Fatigue Strength ◽  
Fatigue Limit ◽  
Room Temperature ◽  
Structural Reliability ◽  
High Cycle Fatigue ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Cyclic Softening ◽  
Fatigue Properties ◽  
Cycle Fatigue

Since high-cycle fatigue loads is applied to the pipes in various energy and chemical plants due to the vibration and frequent temperature change of fluid in the pipes, the high-cycle fatigue behavior of the alloys used for pipes should be understood quantitatively in the structural reliability design of the pipes. The purpose of this study, therefore, is to clarify the high-cycle fatigue strength and fracture mechanism of the modified 9Cr-1Mo steel at temperatures higher than 400°C. This material is one of the effective candidates for the pipes in fast breeder demonstration reactor systems. A rotating bending fatigue test was applied to samples at 50 Hz in air. The stress waveform was sinusoidal and the stress ratio was fixed at −1. The fatigue limit was observed at room temperature and it was about 420 MPa. This value was lower than the 0.2% proof stress of this alloy by about 60 MPa. This decrease can be attributed to the cyclic softening of this material. The limited cycles at knee point was about 8×105 cycles. All fracture was initiated from a single surface crack and no inclusion-induced fracture was observed in the fracture surface by SEM. Thus, the high-cycle fatigue design based on the fatigue limit may be applicable to the modified 9Cr-1Mo steel at room temperature. The fatigue limit of about 350 MPa was also observed at 400°C, and it appeared at about 107 cycles, while it appeared at around 106 cycles at room temperature. Thus, it was confirmed that the fatigue strength of this alloy decrease with temperature. However, the fatigue limit didn’t appear at 550°C up to 108 cycles. The fatigue limit may disappear in this alloy at 550°C. It is very important, therefore, to evaluate the ultra-high cycle fatigue strength of this alloy at temperatures higher than 400°C.

scholarly journals High-cycle fatigue behavior of Co-based superalloy 9CrCo at elevated temperatures

2016 ◽  
Vol 29 (5) ◽  
pp. 1405-1413 ◽  
Author(s):  
Aoshuang Wan ◽  
Junjiang Xiong ◽  
Zhiyang Lyu ◽  
Kuang Li ◽  
Yisen Du ◽  
...  
Keyword(s):  
High Cycle Fatigue ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Cycle Fatigue
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