scholarly journals Effects of Laser Peening Treatment on High Cycle Fatigue Strength and Fatigue Crack Behaviors under Axial Loading of Aluminum Alloy

2010 ◽  
Vol 59 (12) ◽  
pp. 932-937 ◽  
Author(s):  
Yasuo OCHI ◽  
Takashi MATSUMURA ◽  
Takaaki IKARASHI ◽  
Kiyotaka MASAKI ◽  
Toshifumi KAKIUCHI ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Axial Loading ◽  
Laser Peening ◽  
Cycle Fatigue

OS1507 Improvement of high cycle fatigue strength reliability by laser peening treatment in aluminum alloy

2008 ◽  
Vol 2008 (0) ◽  
pp. _OS1507-1_-_OS1507-2_
Author(s):  
Yuji SUZUKI ◽  
Yasuo OCHI ◽  
Takashi MATSUMURA ◽  
Toshihumi KAKIUCHI ◽  
Kiyotaka MASAKI ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Laser Peening ◽  
Cycle Fatigue

Effects of Laser Peening Treatment on High Cycle Fatigue and Crack Propagation Behaviors in Austenitic Stainless Steel

2009 ◽  
Author(s):  
Yasuo Ochi ◽  
Kiyotaka Masaki ◽  
Takashi Matsumura ◽  
Takaaki Ikarashi ◽  
Yuji Sano
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Surface Layer ◽  
Fatigue Crack ◽  
Fatigue Strength ◽  
Crack Propagation ◽  
Compressive Residual Stress ◽  
High Cycle Fatigue ◽  
Laser Peening ◽  
Cycle Fatigue

Laser peening without protective coating (LPwC) treatment is one of surface enhancement techniques using impact wave of high pressure plasma induced by laser pulse irradiation. One of the effects of the LPwC treatment is expected to reduce the tensile residual stress and to induce the compressive residual stress in the surface layer of metallic materials. As a laser has no reaction force due to irradiation and also it has easy characteristics for remote control, the LPwC treatment is practically used as a technique for preventing the stress corrosion cracking (SCC) and for improving the fatigue strength of some structural materials. In this study, high cycle fatigue tests with four-points rotating bending loading were carried out on the non-peened and the LPwC treated low-carbon type austenitic stainless steel 316L in order to investigate the effects of the LPwC treatment on the high cycle fatigue strength and the surface fatigue crack propagation behavior. Two types of specimens were prepared; one was a smooth specimen, the other was a specimen with a pre-crack by the fatigue loading from a small artificial hole. As the results of the LPwC treatment, the high compressive residual stress was induced in the surface layer on the specimens, and the region of the compressive residual stress was about 1mm depth from the surface. The fatigue strength of the LPwC treated SUS316L was remarkably improved during the whole regime of the fatigue life up to the 108 cycles compared with the non-peened materials. Through the fracture mechanics investigation of the pre-cracked materials after the LPwC treatment, it became clear that the fatigue crack propagation was restrained by the LPwC treatment on the pre-cracked region, when the stress intensity factor range ΔK on the crack tip was under the value of 7.6 MPa√m.

Investigations on the Fatigue Property of the High-Strength and Toughness 211Z Casting Aluminium Alloy

2013 ◽  
Vol 423-426 ◽  
pp. 197-201
Author(s):  
Xiao Min Zhang ◽  
Jian Mao ◽  
Yun Che ◽  
Zhong Ke Zhang
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Testing Machine ◽  
High Strength ◽  
Cycle Fatigue ◽  
Fracture Appearance ◽  
Casting Aluminum Alloy ◽  
Casting Aluminum ◽  
Strength And Toughness

211Z is a new type of high strength and toughness Al-Cu-Mn casting aluminum alloy. With the aid of GPS-100 high-cycle fatigue testing machine and DDL100 multifunction tensile testing machine, conventional mechanics performance tests and high-cycle fatigue tests were carried out in this paper. The conventional mechanical property results show that the tensile strength is 477.5 MPa, the theory yield strength is 397.5 MPa and the elongation is 6.625%. Fatigue experiments were performed with load control at room temperature and R =-1 in ambient air. The tensile and compression fatigue strength is 130 MPa under ten million times fatigue test, and S-N fatigue life curve of this alloy was also given in the investigations. 211Z casting aluminum alloy possessing high fatigue strength can be attributed to the fact that it owns high strength and good plasticity simultaneously. The microstructure analysis of fatigue fracture appearance shows that, the fatigue crack initiation behavior of this aluminium alloys depends mainly on the region possessing defects under the surface, there has only one crack source, which means it is belongs to low nominal stress unidirectional bending. In the crack growth stage, the width of fatigue striations decreases with the increase of stress, and a few secondary cracks were found in this stage. When cracks finally losed stability, an instantaneous fracture occured in the investigated samples. Shear lips and dimples were found in the fracture appearance and the final fracture is belongs to ductile fracture.

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.

scholarly journals Effect of Yttrium Content on the Ultra-High Cycle Fatigue Behavior of Mg-Zn-Y-Zr Alloys

2015 ◽  
Vol 816 ◽  
pp. 333-336 ◽  
Author(s):  
D.K. Xu ◽  
E.H. Han
Keyword(s):  
Fatigue Crack ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Slip Bands ◽  
Long Life ◽  
Ultra High Cycle Fatigue ◽  
Hardness Values ◽  
Zr Alloys

In the super-long life regime, the fatigue behavior of as-extruded Mg-6wt%Zn-xY-0.8wt%Zr Mg alloys with Y content of 0, 1, 2 and 3 wt% have been investigated, respectively. The result indicated that for all measured S-N curves, a plateau existed in the regime of 5×106-108 cyc, and then the fatigue strength gradually decreased between 108 and 109 cycles. Therefore, only fatigue strength corresponding to 109 cycles can be determined. Compared with other alloys, the alloy with Y content of 2 wt% has the highest fatigue strength and its value is 105 MPa. SEM observations to fracture surfaces revealed that for all alloys, the fatigue crack mostly initiated at the surface or subsurface of samples failed within 106-109 cycles. Further observation indicated that the crack initiation was related with activated slip bands instead of phase particles and activated twins. Based on the measured results and Murakami equation, it demonstrates that the fatigue strength of alloys is more dependent on the hardness values.

Fatigue Performance of High-Pressure Waterjet-Peened Aluminum Alloy

2001 ◽  
Vol 124 (1) ◽  
pp. 118-123 ◽  
Author(s):  
M. Ramulu ◽  
S. Kunaporn ◽  
M. Jenkins ◽  
M. Hashish ◽  
J. Hopkins
Keyword(s):  
High Pressure ◽  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
High Cycle Fatigue ◽  
Cycle Fatigue

An experimental study of high-pressure waterjet peening on 7075-T6 aluminum alloy was conducted to investigate the effects of waterjet on high-cycle fatigue life and fatigue crack growth. Unnotched hourglass-shaped circular cross section test specimens were fatigue tested in completely reversed rotating bending R=Smin/Smax=−1 to determine fatigue life behavior (S-N curves). Single-edge-notched flat tensile test specimens were tested in the tension-tension fatigue crack growth tests R=Smin/Smax=0.1 to determine fatigue crack propagation behavior (da/dN versus ΔK). Surface characteristics and fracture surfaces were evaluated by scanning electron microscopy (SEM). Results show that waterjet peening can increase high-cycle fatigue life, delay fatigue crack initiation, and decrease the rate of fatigue crack propagation.

Fatigue Test of Al-3%Ti Using Axial Loading Testing Machine for RF MEMS Switch

2006 ◽  
Vol 110 ◽  
pp. 3-8 ◽  
Author(s):  
Jun Hyub Park ◽  
Chang Seung Lee ◽  
Yun Jae Kim
Keyword(s):  
Thin Film ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Rf Mems ◽  
Testing Machine ◽  
Axial Loading ◽  
Tensile Tests ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Mems Switch

This paper presents high cycle fatigue properties of a Al-3%Ti thin film, used in a RF (radio-frequency) MEMS switch for a mobile phone. The thickness and width of the thin film of specimen are 1.1μm and 480.0μm, respectively. Tensile tests of five specimens are performed, from which the ultimate strength is found to be 144MPa. High cycle fatigue tests of six specimens are also performed, from which the fatigue strength coefficient and the fatigue strength exponent are found to be 336MPa and –0.1514, respectively.

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