Cyclic deformation and fatigue behavior of 7075-T651 Al alloy with a gradient structure

Author(s):  
Zepeng Liu ◽  
Hongxia Zhang ◽  
Zhifeng Yan ◽  
Peter K. Liaw ◽  
Peng Dong
2008 ◽  
Vol 22 (31n32) ◽  
pp. 5477-5482 ◽  
Author(s):  
ATSUMICHI KUSHIBE ◽  
TSUTOMU TANAKA ◽  
YORINOBU TAKIGAWA ◽  
KENJI HIGASHI

The crack propagation properties for ultrafine-grained Zn -22 wt % Al alloy during low cycle fatigue (LCF) in the superplastic region and the non-superplastic region were investigated and compared with the corresponding results for several other materials. With the Zn - 22 wt % Al alloy, it was possible to conduct LCF tests even at high strain amplitudes of more than ±5%, and the alloy appeared to exhibit a longer LCF lifetime than the other materials examined. The fatigue life is higher in the superplastic region than in the non-superplastic region. The rate of fatigue crack propagation in the superplastic region is lower than that in the other materials in the high J-integral range. In addition, the formation of cavities and crack branching were observed around a crack tip in the supereplastic region. We therefore conclude that the formation of cavities and secondary cracks as a result of the relaxation of stress concentration around the crack tip results in a reduction in the rate of fatigue crack propagation and results in a longer fatigue lifetime.


2009 ◽  
pp. 1218-1218-19
Author(s):  
Conle A ◽  
Oxland TR ◽  
Topper TH

2020 ◽  
Vol 1002 ◽  
pp. 21-32
Author(s):  
Ahmed R. Alhamaoy ◽  
Ghanim Sh. Sadiq ◽  
Furat I. Hussein ◽  
S.N. Ali

The optimal combination of aluminum quality, sufficient strength, high stress to weight ratio and clean finish make it a good choice in driveshafts fabrication. This study has been devoted to experimentally investigate the effect of applying laser shock peening (LSP) on the fatigue performance for 6061-T6 aluminum alloy rotary shafts. Q-switched pulsed Nd:YAG laser was used with operating parameters of 500 mJ and 600 mJ pulse energies, 12 ns pulse duration and 10 Hz pulse repetition rate. The LSP is applied at the waist of the prepared samples for the cyclic fatigue test. The results show that applying 500 mJ pulse energy yields a noticeable effect on enhancing the fatigue strength by increasing the required number of cycles to fracture the sample. In addition, the effect on increasing the pulse energy from 500 mJ to 600 mJ shows a significant effect in term of creating the endurance limit for the samples.


2014 ◽  
Vol 891-892 ◽  
pp. 1231-1236 ◽  
Author(s):  
Andreas Sorich ◽  
Marek Smaga ◽  
Dietmar Eifler

The austenitic steel X6CrNiNb1810 (AISI 347) was investigated in isothermal total strain-controlled tests at ambient temperature and T = 300 °C in the LCF-and HCF-range. The phase transformation from paramagnetic austenite (fcc) into ferromagnetic α´-martensite ́(bcc) leads to cyclic hardening and to an increase in fatigue life. At 300 °C no α´-martensite formation was observed in the LCF-range and the cyclic deformation behavior depends basically on cyclic hardening processes due to an increase of the dislocation density, followed by cyclic saturation and softening due to changes in the dislocation structure. In the HCF-range an increase in fatigue life was observed due to ε- and α´-martensite formation. Measurements of the mechanical stress-strain-hysteresis as well as temperature and magnetic properties enable a characterization of the cyclic deformation behavior and phase transformation in detail. The changes in the physical data were interpreted via microstructural changes observed by scanning-and transmission-electron-microscopy as well as by x-ray investigations. Additionally electromagnetic acoustic transducers (EMATs) developed from the Fraunhofer Institute of Non-destructive Testing (IZFP) Saarbrücken were used for an in-situ characterization of the fatigue processes.


Sign in / Sign up

Export Citation Format

Share Document