Super Long Life Fatigue of AE42 and AM60 Magnesium Alloys

2006 ◽  
Vol 306-308 ◽  
pp. 181-186
Author(s):  
Q.Y. Wang ◽  
Hong Yan Zhang ◽  
S.R. Sriraman ◽  
S.L. Liu
Keyword(s):  
Magnesium Alloys ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Horizontal Asymptote ◽  
Ultrasonic Fatigue ◽  
Reversed Loading ◽  
Fatigue Characteristics ◽  
Long Life ◽  
Very High

Magnesium alloys, on account of their lightweight, find useful applications in the automotive sector. During service, they experience very high number of fatigue cycles. Therefore, the understanding of their long life fatigue behavior becomes extremely important. This is possible by using ultrasonic fatigue testing, which is the only feasible way of doing it. In this study, the two such alloys viz. AE42 and AM60 has been investigated for their long life fatigue characteristics under fully reversed loading conditions, using a piezoelectric fatigue testing machine operating at a frequency of 20 kHz. The S-N data does not reach a horizontal asymptote at 107 cycles in either of the alloys. However, the alloy AM60 seems to show a fatigue limit at about at 109 cycles. The fractures examined by scanning electron microscopy (SEM) were found to be brittle in character. In very high cycle fatigue conditions, the crack was found to initiate from the specimen subsurface.

Fatigue in Ti-6Al-4V at Very High Cycles

2007 ◽  
Vol 561-565 ◽  
pp. 259-262 ◽  
Author(s):  
X.J. Cao ◽  
M.R. Sriraman ◽  
Qing Yuan Wang
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Weight Ratio ◽  
High Strength ◽  
Ambient Air ◽  
Ti Alloys ◽  
Structural Applications ◽  
Ultrasonic Fatigue ◽  
Reversed Loading ◽  
Very High

The importance of determining and understanding the very high cycle fatigue behaviors of materials has gained strength in recent years. Ti-alloys, in view of their high strength-to-weight ratio, have a range of structural applications. Of these, Ti-6Al-4V, belonging to the alpha-beta type is the most widely used. The present paper deals with investigations on the fatigue behavior of TC4, the Chinese equivalent to Ti-6Al-4V, up to very high cycles. Fatigue testing was carried out on a piezoelectric ultrasonic fatigue machine operating at 20 kHz frequency. Hourglass shaped resonant specimens were tested in ambient air at room temperature under completely reversed loading conditions (R = -1). Failure in the alloy was seen to occur right up to the gigacycle regime, with the fractures being found to initiate from the surface unlike in steels. The fracture surfaces exhibit brittle characteristics containing river patterns and cleavage facets, as well as striations.

Very Long Life Fatigue Behavior of Bearing Steel AISI 52100

2005 ◽  
Vol 297-300 ◽  
pp. 1846-1851 ◽  
Author(s):  
Q.Y. Wang ◽  
Hong Yan Zhang ◽  
M.R. Sriraman ◽  
Shou Xin Li
Keyword(s):  
Fatigue Limit ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Bearing Steel ◽  
Aisi 52100 ◽  
Steel Aisi ◽  
Reversed Loading ◽  
Long Life ◽  
Number Of Cycles

For many applications, the understanding of very long life fatigue in materials becomes extremely important. In this study, the fatigue behavior of bearing steel GCr15 (conforming to AISI 52100) at very high number of cycles has been examined. Experiments on hourglass specimens were conducted in air at room temperature, for fully reversed loading condition (R=-1), using a piezoelectric fatigue testing machine operating at a frequency of 20kHz. The results indicate that the S-N data does not reach a horizontal asymptote (signifying the fatigue limit) at 107 cycles, as conventionally believed, and that the material can fracture up to 109 cycles. Therefore, to quote a fatigue limit at 107 cycles may not hold good for the material studied. The influence of defects (such as inclusions) on the crack initiation and fracture was analyzed by scanning electron microscopy.

Gigacycle Fatigue of Welded Joints of Structural Materials (A Review)

2016 ◽  
Vol 17 ◽  
pp. 14-30 ◽  
Author(s):  
Okechukwu P. Nwachukwu ◽  
Alexander V. Gridasov ◽  
Ekaterina A. Gridasova
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Testing Machine ◽  
Structural Materials ◽  
Fatigue Tests ◽  
Material Defects ◽  
Graphite Cast Iron ◽  
Ultrasonic Fatigue ◽  
Materials Used ◽  
Fatigue Failures

This review looks into the state of gigacycle fatigue behavior of some structural materials used in engineering works. Particular attention is given to the use of ultrasonic fatigue testing machine (USF-2000) due to its important role in conducting gigacycle fatigue tests. Gigacycle fatigue behavior of most materials used for very long life engineering applications is reviewed.Gigacycle fatigue behavior of magnesium alloys, aluminum alloys, titanium alloys, spheroid graphite cast iron, steels and nickel alloys are reviewed together with the examination of the most common material defects that initiate gigacycle fatigue failures in these materials. In addition, the stage-by-stage fatigue crack developments in the gigacycle regime are reviewed. This review is concluded by suggesting the directions for future works in gigacycle fatigue.

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.

Very High Cycle Fatigue in Pulsed High Power Spallation Neutron Source

2014 ◽  
Vol 891-892 ◽  
pp. 536-541 ◽  
Author(s):  
Zhi Hong Xiong ◽  
Masatoshi Futakawa ◽  
Takashi Naoe ◽  
Katsuhiro Maekawa
Keyword(s):  
Strain Rate ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Air Cooling ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Neutron Spallation Source ◽  
Ultrasonic Fatigue ◽  
Very High

Very high cycle fatigue degradation of type 316L austenitic stainless steel, which is used as the structural material of neutron spallation sources under intensive neutron irradiation environment, is investigated by using an ultrasonic fatigue testing machine. The strain rate imposed on the structure of neutron spallation source is almost equivalent to that produced in the testing machine. The temperature on the surface was controlled by the air-cooling. The effect of strain rate on the fatigue strength is recognized to increase the fatigue limit.

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 Bridge Steel in Very Long Life Region

2010 ◽  
Vol 452-453 ◽  
pp. 269-272
Author(s):  
Yan Nu ◽  
Yi Yan Chen ◽  
Rui Juan Jiang ◽  
Dong Hui Fang ◽  
Qing Yuan Wang
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Loading Frequency ◽  
Mass Defect ◽  
Testing Technique ◽  
Bridge Steel ◽  
Ultrasonic Fatigue ◽  
Long Life ◽  
Corrugated Steel Web ◽  
Number Of Cycles

Q345qC steel is widely used in corrugated steel web. In this paper, the fatigue strength of Q345qC steel between 105~109 cycles was investigated using the ultrasonic fatigue testing technique, with a loading frequency of 20 kHz. The fracture surfaces of specimens were observed with scanning electron microscopy (SEM). The experimental results show that the S-N curve of Q345qC steel continues to decrease with the increase of the number of cycles between 105 and 109 cycles and does not generally exhibit a plateau beyond 107 cycles. The observation of fracture surface shows that the mechanism of fatigue failure is similar in both case of ultrasonic fatigue and conventional fatigue in long life regime. Cracks initiate from a mass defect of specimen surface or an interior inclusion.

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.

Sign in / Sign up

Export Citation Format

Share Document