High cycle fatigue behavior of Al1070 alloy severely deformed by equal channel angular pressing process

2016 ◽  
Vol 232 (6) ◽  
pp. 514-519 ◽  
Author(s):  
Mohammad Bagher Limooei ◽  
Morteza Zandrahimi ◽  
Ramin Ebrahimi
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Equal Channel Angular Pressing ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Pure Aluminum ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Angular Pressing ◽  
Pressing Process

In the present work, equal channel angular pressing of commercial pure aluminum 1070 was performed up to 4 passes using route Bc. For equal channel angular pressing operation, a suitable die set was designed and manufactured. X-ray diffraction analysis was used to determine the microstructure of the equal channel angular pressing-ed material. The fracture surface morphology and microstructure after fatigue were investigated by scanning electron microscopy. Mechanical properties of the equal channel angular pressing-ed material were evaluated by hardness and tension tests. Also, cyclic deformation behavior of severe plastic deformation Al1070 has been studied and results show a significant variation in hardness, ultimate strength and fatigue properties in high cycle fatigue life. Coefficient of fatigue strength σ′f and Bridgman correction factor have been obtained by S-N curve and tension test specimens, respectively, and compared before and after equal channel angular pressing process. Also an useful relation has been derived between fatigue life ( Nf) and stress amplitude ( σa) in high cycle fatigue region. Results indicated that there was not clear relation between fatigue strength coefficient and true corrected fracture stress in this case.

The Effects of Specimen Size on the Very High Cycle Fatigue Properties of FV520B-I

2015 ◽  
Author(s):  
Ming Zhang ◽  
Weiqiang Wang ◽  
Aiju Li
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Specimen Size ◽  
Fatigue Properties ◽  
Test Results ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Heat Effects ◽  
Very High

The authors researched the effects of specimen size on the very high cycle fatigue properties of FV520B-I through ultrasonic fatigue testing. The test results showed that the very high cycle fatigue mechanism was not changed and the fatigue properties declined as the specimen size increased. The S-N curve moved downward and the fatigue life decreased under the same stress level maybe due to the heat effects of large specimens in tests. The fatigue strength and the fatigue life were predicted by relevant models. The prediction of fatigue strength was close to test result, and the prediction of fatigue life was less effective compared with the previous prediction of small size specimen test results.

scholarly journals Effect of Carburizing and Nitriding on Fatigue Properties of 18Cr2Ni4WA Steel in Very High Cycle Fatigue Regime

2021 ◽  
Vol 45 (3) ◽  
pp. 207-215
Author(s):  
Zhenduo Sun ◽  
Dongbo Hou ◽  
Wei Li
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Internal Defect ◽  
Surface Fatigue ◽  
Very High Cycle Fatigue ◽  
The Relationship ◽  
Very High

The work aims to study the influence of carburizing and nitriding on fatigue properties of 18Cr2Ni4WA high strength steel in very high cycle fatigue regime. Very high cycle fatigue tests were carried out on 18Cr2Ni4WA Steel after carburizing and nitriding respectively. The micro morphology of fatigue fracture was observed by scanning electron microscope, the failure mode and failure mechanism were discussed. The relationship between fatigue life and defect size, FGA size, fish eye size of fracture was analyzed. The characteristic size of defects is evaluated by Gumbel, Weibull and GEV distribution functions, and a modified Akiniwa fatigue life prediction model considering the relationship between FGA size and inclusion size was established. The results showed that, nitriding and carburizing treatment improve the surface fatigue limit of the steel. The fatigue life decreases with the increase of internal defect size and FGA size. After carburizing and nitriding treatment, the internal fatigue strength of the specimen decreases slightly. When the failure probability is 99%, the internal defect sizes of nitrided specimens calculated by Weibull, Gumbel and GEV distributions are 141.5 μm, 148.4 μm and 211.7 μm respectively. The calculated internal defect sizes of carburized specimens are 47 μm, 67.8 μm and 40 μm respectively. Compared with the experimental data, the fatigue strength predicted by GEV is the most appropriate. carburizing and nitriding treatment can improve the surface fatigue strength of 18Cr2Ni4WA steel, but slightly reduce the internal fatigue strength. The prediction result of the new model is conservative when the failure probability is 99%, which is suitable for engineering application.

An energetic method to evaluate the macro and micro high-cycle fatigue behavior of the aluminum alloy

2017 ◽  
Vol 232 (8) ◽  
pp. 1456-1469 ◽  
Author(s):  
Junling Fan ◽  
Xinglin Guo ◽  
Yanguang Zhao
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Energy Dissipation ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Thermal Signal ◽  
Dissipation Mechanism ◽  
Good Agreement

An energetic method is proposed to rapidly evaluate the macro- and microfatigue behavior of aluminum alloy in high-cycle fatigue. The theoretical correlation between the thermal signal and the energy dissipation during the fatigue process is established for the irreversible dissipation mechanism description. The energetic method is applied to predict the fatigue strength and the entire fatigue life of the aluminum alloy. Moreover, the energy dissipation is properly used to evaluate the microplastic behavior at the grain scale, which is responsible for the progressive movements of the internal microstructures. Experiments were carried out to validate the current energetic method, and good agreement was obtained between the predicted results and the traditional results. Thus, the current energetic method is confirmed to be promising for the macro and micro high-cycle fatigue behavior assessment.

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.

Super Long Life Fatigue Properties of Rail Steel U71Mn and U75V

2013 ◽  
Vol 690-693 ◽  
pp. 1753-1756
Author(s):  
Ze Fu Luo ◽  
Shi Ming Cui ◽  
Yan Zeng Wu ◽  
Qing Yuan Wang
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Rail Steel ◽  
Fatigue Behavior ◽  
Test System ◽  
Railway Track ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

Railway track steel, U71Mn and U75V were fatigued in this study, with the help of ultrasonic fatigue test system, to investigate the high cycle fatigue life behaviors. The results showed that the fatigue damage still occurs when the fatigue life exceeds 107, and the evolution of S-N curve showed a ladder type. This test showed that the traditional view of fatigue design and life prediction method were unable to meet the requirements of machinery and equipment working in gigacycle fatigue range, very high cycle fatigue behavior of fatigue has become a major challenge for researchers. The scanning electron microscope analysis of crack initiation was performed to clarify the mechanism of very high cycle fatigue failure.

Specimen Size Effect on Fatigue Properties of Surface-Micromachined Al-3%Ti Thin Films

2007 ◽  
Author(s):  
Jun-Hyub Park ◽  
Man Sik Myung ◽  
Yun-Jae Kim
Keyword(s):  
Thin Film ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Evaluation Method ◽  
High Cycle Fatigue ◽  
Test Procedure ◽  
Fatigue Tests ◽  
Test Method ◽  
Fatigue Properties ◽  
Cycle Fatigue

This paper presents high cycle fatigue properties of an Al-3%Ti thin film, used in a RF (radio-frequency) MEMS switch for a mobile phone and also describes new test method for obtaining static and dynamic characteristics of thin film and reliability evaluation method on MEMS device with thin film developed by authors. Durability should be ensured for such devices under cycling load. Therefore, with the proposed specimen and test procedure, tensile and fatigue tests were performed to obtain mechanical and fatigue properties. The specimen was made with dimensions of 1000μm long, 1.0μm thickness, and 3 kinds of width, 50, 100 and 150μm. High cycle fatigue tests for each width were also performed, from which the fatigue strength coefficient and the fatigue strength exponent were found to be 193MPa and −0.02319 for 50μm, 181MPa and −0.02001 for 100μm, and 164MPa and −0.01322 for 150μm, respectively. We found that the narrower specimen is, the longer fatigue life of Al-3%Ti is and the wider specimen is, the more susceptible to stress level fatigue life of Al-3%Ti was.

Effect of fisheye failure on material performance inducing error circle under high cycles

2021 ◽  
pp. 105678952110200
Author(s):  
Haiyan Ge ◽  
Xintian Liu ◽  
Xu Wang ◽  
Xiaolan Wang ◽  
Haijie Wang
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Engineering Application ◽  
High Strength ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Ultra High Cycle Fatigue ◽  
Strength Models ◽  
Error Circle

In the engineering application of high strength steel and surface strengthening steel, fisheye failure is often happened in high cycle fatigue. To explore the effect of fisheye failure on high cycle fatigue properties of materials, a high cycle fatigue life model was established based on the Murakami and Tanaka’s fatigue strength models. The model introduces the error circle to evaluate fisheye size, and discusses the influencing factors of fatigue strength. The results show that the size and depth of fisheye failure will affect performance of materials. The proposed model considering the size and depth of defect quantitatively shows the influence of fisheye details on material performance, and effectively predicts the high/ultra-high cycle fatigue life.

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