Investigation of Very High Cycle Fatigue Behavior of TC17 Alloy

2011 ◽  
Vol 295-297 ◽  
pp. 1311-1314
Author(s):  
Li Cheng ◽  
Chao Gao ◽  
Jing Sheng Shen ◽  
Ning Li ◽  
Wei Chen ◽  
...  
Keyword(s):  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Tests ◽  
Test Technique ◽  
Bending Fatigue ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Very High ◽  
Ultrasonic Fatigue Test

According to the loading characteristics of engine blades, a vibration bending fatigue system by using the ultrasonic fatigue test technique has been developed and the specimen is designed by finite element method, fatigue tests of TC17 between 106and 109cycles have been completed in this paper. The results show that the fatigue life of specimen increases over 107cycles and the initiation of fatigue cracks transfers from only in the surface of specimen to both in the surface and the sub-surface with loading decreasing.

scholarly journals Recent Advances in Very High Cycle Fatigue Behavior of Metals and Alloys—A Review

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1200
Author(s):  
Ashutosh Sharma ◽  
Min Chul Oh ◽  
Byungmin Ahn
Keyword(s):  
Crack Initiation ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Simulation Studies ◽  
Cycle Fatigue ◽  
Future Directions ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Very High

We reviewed the research and developments in the field of fatigue failure, focusing on very-high cycle fatigue (VHCF) of metals, alloys, and steels. We also discussed ultrasonic fatigue testing, historical relevance, major testing principles, and equipment. The VHCF behavior of Al, Mg, Ni, Ti, and various types of steels were analyzed. Furthermore, we highlighted the major defects, crack initiation sites, fatigue models, and simulation studies to understand the crack development in VHCF regimes. Finally, we reviewed the details regarding various issues and challenges in the field of VHCF for engineering metals and identified future directions in this area.

Effect of shot peening on very high cycle fatigue of 2024-T351 aluminium alloy

2020 ◽  
Vol 10 (7) ◽  
pp. 1032-1039
Author(s):  
Renhui Tian ◽  
Jiangfeng Dong ◽  
Yongjie Liu ◽  
Qingyuan Wang ◽  
Yunrong Luo
Keyword(s):  
Fracture Surface ◽  
Crack Initiation ◽  
Shot Peening ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Fatigue Strength Improvement ◽  
Ultrasonic Fatigue ◽  
Very High

To investigate the influence of shot peening (SP) on very high cycle fatigue (VHCF) performance of 2024-T351, the specimens with three surface conditions were performed under ultrasonic fatigue tests: mechanicallypolished without peening (NP), ceramic shot peening (SP1), steel and glass mixed shot peening (SP2). The roughness, microhardness, residual stress, fractography measurement and scanning electron microscopy (SEM) were applied before fatigue test to characterize the effective layer induced by the peening treatment. For the failed specimens, the fracture surface were analysed using SEM to study the mechanisms of fatigue crack propagation. In addition, the fatigue life curve in ultra-high cycle region continuously decreased in the three series of specimens. However, the experimental results revealed that fatigue strength improvement resulting from shot peening treatment was negligible in very high cycle regime. Furthermore, the stress intensity factor for the surface crack initiation (SCI) and interior crack initiation (ICI) was discussed based on quantitative analysis on the fracture surface. The average values of ΔKfish-eye for NP, SP1 and SP2 specimens are about 2.22, 1.48 and 1.61 MPa · m1/2, respectively.

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.

Very High Cycle Fatigue Properties of Welded Joints under High Frequency Loading

2013 ◽  
Vol 647 ◽  
pp. 817-821
Author(s):  
Chao He ◽  
Yong Jie Liu ◽  
Qing Yuan Wang
Keyword(s):  
Base Metal ◽  
Welded Joints ◽  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
Ambient Air ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Very High

Very high cycle fatigue (VHCF) properties of welded joints under ultrasonic fatigue loading have been investigated for titanium alloy (TI-6Al-4V) and bridge steel (Q345). Ultrasonic fatigue tests of base metal and welded joints were carried out in ambient air at room temperature at a stress ratio R=-1. It was observed that the fatigue strength of welded joints reduced by 50-60% as compared to the base metal. The S-N fatigue curves in the range of 107~109 cycles of base metal and welded joints for both materials exhibited the characteristic of continually decreasing type. The fatigue failure still occurred after 107 cycles of loading, and the fatigue limit in traditional does not exist. The fatigue facture mainly located in the weld metal region at low cycle fatigue range, but in the fusion area in HCF and VHCF. Analysis of fracture surfaces analyzed by SEM revealed that the fatigue cracks initiated from welding defects such as pores, cracks and inclusions.

scholarly journals Effect of Aqueous Environment on High Cycle and Very-High-Cycle Fatigue Behavior for a Structural Steel

2011 ◽  
Vol 462-463 ◽  
pp. 355-360
Author(s):  
You Shi Hong ◽  
Gui An Qian
Keyword(s):  
Fatigue Strength ◽  
Structural Steel ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Aqueous Environment ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

In this paper, rotary bending fatigue tests for a structural steel were performed in laboratory air, fresh water and 3.5% NaCl aqueous solution, respectively, thus to investigate the influence of environmental media on the fatigue propensity of the steel, especially in high cycle and very-high-cycle fatigue regimes. The results show that the fatigue strength of the steel in water is remarkably degraded compared with the case tested in air, and that the fatigue strength in 3.5% NaCl solution is even lower than that tested in water. The fracture surfaces were examined to reveal fatigue crack initiation and propagation characteristics in air and aqueous environments.

Very high cycle fatigue behavior of dissimilar martensitic stainless-steel diffusion-bonded joints

2019 ◽  
Vol 9 (9) ◽  
pp. 1120-1126
Author(s):  
Baohua Nie ◽  
Zihua Zhao ◽  
Dongchu Chen ◽  
Fangjun Liu ◽  
Jishi Zhao ◽  
...  
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Property ◽  
Bonded Joints ◽  
Cycle Fatigue ◽  
Shape Characteristic ◽  
Very High Cycle Fatigue ◽  
Very High

Very high cycle fatigue (VHCF) behavior of the diffusion bonded joints between 3Cr13 and 2Cr13 were investigated. Results showed that the diffusion bonded joints obtained a comparable fatigue property of 2Cr13, and the S–N curves exhibited a decreasing shape characteristic. However, fatigue life was dramatically decreased by occasional non-diffusion defects. Fatigue cracks in diffusion bonded joints occurred at specimen's surface in high cycle regimes, whereas VHCF cracks were originated from inclusions on the side of 2Cr13 based materials, in which the fine granular area (FGA) characteristics were observed around the internal inclusion. Furthermore, fatigue strength of the diffusion joints was interpreted based on the Murakami model. The crack propagation life estimated by Paris-Hertzberg-McClintock model mainly contributed for the fatigue life of the specimens with occasional non-fusion defects, in which non-fusion defects acted as pre-cracks.

Ultrasonic Fatigue of CFRP - Experimental Principle, Damage Analysis and Very High Cycle Fatigue Properties

2017 ◽  
Vol 742 ◽  
pp. 621-628 ◽  
Author(s):  
Dominic Weibel ◽  
Frank Balle ◽  
Daniel Backe
Keyword(s):  
Carbon Fiber ◽  
Matrix Composite ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Polyphenylene Sulfide ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Very High

Structural aircraft components are often subjected to more than 108 loading cycles during their service life. Therefore the increasing use of carbon fiber reinforced polymers (CFRP) as primary lightweight structural materials leads to the demand of a precise knowledge of the fatigue behavior and the corresponding failure mechanisms in the very high cycle fatigue (VHCF) range. To realise fatigue investigations for more than 108 loading cycles in an economic reasonable time a novel ultrasonic fatigue testing facility (UTF) for cyclic three-point bending was developed and patented. To avoid critical internal heating due to viscoelastic damping and internal friction, the fatigue testing at 20 kHz is performed in resonance as well as in pulse-pause control resulting in an effective testing frequency of ~1 kHz and the capability of performing 109 loading cycles in less than twelve days. The fatigue behavior of carbon fiber twill 2/2 fabric reinforced polyphenylene sulfide (CF-PPS) and carbon fiber 4-H satin fabric reinforced epoxy resin (CF-EP) was investigated. To study the induced fatigue damage of CF-PPS and CF-EP in the VHCF regime in detail, the fatigue mechanisms and damage development were characterized by light optical and SEM investigations during interruptions of constant amplitude tests (CAT). Lifetime-oriented investigations showed a significant decrease of the bearable stress amplitudes of CF-PPS and CFEP in the range between 106 to 109 loading cycles. The ultrasonically fatigued thermoset matrix composite showed a significantly different VHCF behavior in comparison to the investigated thermoplastic matrix composite: No fiber-matrix debonding or transversal cracks were present on the specimen edges, but a sudden specimen failure along with carbon fiber breakage have been observed. The fatigue shear strength at 109 cycles for CF-PPS could be determined to τa, 13 = 4.2 MPa and to τa, 13 = 15.8 MPa for the thermoset material CF-EP.

Fatigue Behavior of GH4169 Alloy up to Very High Cycles

2012 ◽  
Vol 535-537 ◽  
pp. 928-931
Author(s):  
Xiao Zhao ◽  
Jian Jun Zhao ◽  
Yong Jie Liu
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Experimental Studies ◽  
Fatigue Property ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Reversed Cyclic ◽  
Very High ◽  
Gh4169 Alloy

The present paper deals with experimental studies on the long life fatigue behavior of GH4169 alloy. Using the ultrasonic fatigue testing technique, specimens of hourglass shape were fatigue tested in air at room temperature under fully reversed cyclic loading conditions (R=-1). The very high cycle fatigue property of GH4169 alloy was studied and the initiation mechanisms of fatigue cracks were investigated and analyzed with scanning electron microscopy (SEM) and energy dispersive atomic X-ray (EDX). Preliminary results indicate that the S-N curve displays a bilinear decreasing tendency within 109 cycles and fatigue failure initiates from inclusions/defects on the specimen surface.

scholarly journals Review of Multiaxial Testing for Very High Cycle Fatigue: From ‘Conventional’ to Ultrasonic Machines

Machines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 25
Author(s):  
Pedro Costa ◽  
Richard Nwawe ◽  
Henrique Soares ◽  
Luís Reis ◽  
Manuel Freitas ◽  
...  
Keyword(s):  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Cycle Fatigue ◽  
New Materials ◽  
Multiaxial Testing ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Very High

Fatigue is one of the main causes for in service failure of mechanical components and structures. With the development of new materials, such as high strength aluminium or titanium alloys with different microstructures from steels, materials no longer have a fatigue limit in the classical sense, where it was accepted that they would have ‘infinite life’ from 10 million (107) cycles. The emergence of new materials used in critical mechanical parts, including parts obtained from metal additive manufacturing (AM), the need for weight reduction and the ambition to travel greater distances in shorter periods of time, have brought many challenges to design engineers, since they demand predictability of material properties and that they are readily available. Most fatigue testing today still uses uniaxial loads. However, it is generally recognised that multiaxial stresses occur in many full-scale structures, being rare the occurrence of pure uniaxial stress states. By combining both Ultrasonic Fatigue Testing with multiaxial testing through Single-Input-Multiple-Output Modal Analysis, the high costs of both equipment and time to conduct experiments have seen a massive improvement. It is presently possible to test materials under multiaxial loading conditions and for a very high number of cycles in a fraction of the time compared to non-ultrasonic fatigue testing methods (days compared to months or years). This work presents the current status of ultrasonic fatigue testing machines working at a frequency of 20 kHz to date, with emphasis on multiaxial fatigue and very high cycle fatigue. Special attention will be put into the performance of multiaxial fatigue tests of classical cylindrical specimens under tension/torsion and flat cruciform specimens under in-plane bi-axial testing using low cost piezoelectric transducers. Together with the description of the testing machines and associated instrumentation, some experimental results of fatigue tests are presented in order to demonstrate how ultrasonic fatigue testing can be used to determine the behaviour of a steel alloy from a railway wheel at very high cycle fatigue regime when subjected to multiaxial tension/torsion loadings.

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