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 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

Micromechanics of an Extrusion in High-Cycle Fatigue With Creep

1990 ◽  
Vol 57 (4) ◽  
pp. 815-820 ◽  
Author(s):  
T. H. Lin ◽  
S. R. Lin ◽  
X. Q. Wu
Keyword(s):  
Crack Initiation ◽  
Tensile Strain ◽  
High Cycle Fatigue ◽  
Elevated Temperatures ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Tensor Component ◽  
Shear Stresses ◽  
Cycle Fatigue ◽  
Thin Slice

Extrusions and intrusions often are sites of fatigue cracks. The extent of extrusions is important in fatigue crack initiation. Metals often are subject to fatigue loadings at elevated temperatures. At temperatures below one half of the melting temperature slip is the main mechanism of inelastic deformation. In this study, an aluminum polycrystal loaded in this temperature range is considered. A most favorably oriented crystal located at a free surface of a f.c.c. polycrystal subject to creep under cyclic tension and compression of high-cycle fatigue is considered. An extrusion in this crystal is shown to be produced by a positive slip in one thin slice “P” and a negative slip in a closely located slice “Q”. An initial tensile strain εααI in the thin slice “R” sandwiched between P and Q causes a positive initial shear stress ταβI in P and a negative one in Q. It is shown that the extrusion growth causes a tensile strain in R, which can activate a second slip system giving a creep strain with a tensor component εαα. It has the same effect as the initial strain εααI in causing this difference in shear stresses in P and Q and gives much additional extrusion growth. The extent of intrusion and extrusion is important in this study of crack initiation.

scholarly journals Bending Fatigue Behavior of 316L Stainless Steel up to Very High Cycle Fatigue Regime

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4820
Author(s):  
Yongtao Hu ◽  
Yao Chen ◽  
Chao He ◽  
Yongjie Liu ◽  
Qingyuan Wang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Slip Band ◽  
316L Stainless Steel ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Propagation Mechanism ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

Effect of microstructure on the crack initiation and early propagation mechanism in the very high cycle fatigue (VHCF) regime was studied in 316L stainless steel (316L SS) by atomic force microscope (AFM) and electron back scattered diffraction (EBSD). The results show that small fatigue cracks initiate from the slip band near the grain boundaries (GBs) or the twin boundaries (TBs). Early crack propagation along or cross the slip band is strongly influenced by the local microstructure such as grain size, orientation, and boundary. Besides, the gathered slip bands (SBs) are presented side by side with the damage grains of the run-out specimen. Finally, it is found that dislocations can either pass through the TBs, or be arrested at the TBs.

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

Influence of Subjection to Plasma Nitriding Surface Modifications on Ultra-High Cycle Fatigue Behavior of Ti-6Al-4V

2011 ◽  
Vol 105-107 ◽  
pp. 1731-1735
Author(s):  
Yan Zeng Wu ◽  
Qing Yuan Wang ◽  
Qiao Lin Ouyang
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
High Cycle Fatigue ◽  
Plasma Nitriding ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Surface Modifications ◽  
Test Method ◽  
Cycle Fatigue ◽  
Ultra High Cycle Fatigue

Using the ultrasonic fatigue test method, the influence of subjection to plasma nitriding surface modifications on the ultra-high cycle fatigue behavior of Ti-6Al-4V was investigated, then a comparison with corresponding behaviors of the normal Ti-6Al-4V was made. The results show the S-N curve of Ti-6Al-4V with plasma nitriding surface modifications still continuously declines, no conventional fatigue limit exists for Ti-6Al-4V. Plasma nitriding surface modifications enhance surface hardness, but they make the material fatigue strength decrease by about 17 %. The fractography of fatigue failure has been observed by scanning electron microscopy. The observation shows that fatigue failure initiates from internal of specimen after the fatigue life of 108cycles and fatigue cracks mainly initiate from the surface of specimen before the fatigue life of 108cycles.

Rotary bending high-cycle fatigue behavior of DD32 single crystal superalloy containing rhenium

2012 ◽  
Vol 47 (12) ◽  
pp. 4805-4812 ◽  
Author(s):  
Jinjiang Yu ◽  
Yanhong Yang ◽  
Xiaofeng Sun ◽  
Hengrong Guan ◽  
Zhuangqi Hu
Keyword(s):  
Single Crystal ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Single Crystal Superalloy ◽  
Cycle Fatigue

HIGH CYCLE FATIGUE BEHAVIOR OF A NICKEL--BASED SINGLE CRYSTAL SUPERALLOY DD98M AT 900℃

2013 ◽  
Vol 48 (2) ◽  
pp. 170-175 ◽  
Author(s):  
Guoming HAN ◽  
Zhenxing ZHANG ◽  
Jinguo LI ◽  
Tao JIN ◽  
Xiaofeng SUN ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Single Crystal Superalloy ◽  
Cycle Fatigue

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.

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