Multiaxial Fatigue of 6061-T6 Aluminum Alloy under Corrosive Environment

2016 ◽  
Vol 853 ◽  
pp. 77-82
Author(s):  
Xu Chen ◽  
Rui Si Xing ◽  
Xiao Peng Liu
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Stress Amplitude ◽  
Low Cycle Fatigue ◽  
Cyclic Hardening ◽  
Cyclic Softening ◽  
Fatigue Tests ◽  
Plastic Strain Amplitude ◽  
Multiaxial Fatigue ◽  
Corrosive Environment

Aluminium alloys are widely used in the fields of automobile, machinery and naval construction. To investigate the effect of non-proportional loadings and corrosive environment on the fatigue resistance of 6061-T6 aluminum alloy, a set of uniaxial and multiaxial low cycle fatigue tests were carried out. Firstly, the results of uniaxial tests showed that the alloy exhibited cyclic hardening then cyclic softening. With the increase of stress amplitude the cyclic softening became pronounced. The increasing of plastic deformation was basically cyclically stable with small plastic strain amplitude accumulation when the stress amplitude was lower than 200MPa ,while it was increasing rapidly when the stress amplitude was higher than 220MPa. Secondly, it was observed that non-proportional cycle additional hardening of 6061-T6 aluminum alloy was little. While the fatigue life was badly affected by the loading paths. Thirdly ,the fatigue corrosion interactions were also talked about in details by performing the tests under the same loading conditions with corrosive environment. The experiment proved that the seawater corrosion has huge impact on fatigue life under pH 3. Finally, a multi-axial fatigue life prediction model was used to predict the fatigue life with or without the corrosive environment which showed a good agreement with experimental data.

scholarly journals Multiaxial fatigue behavior of 2618 aluminum alloy

2019 ◽  
Vol 300 ◽  
pp. 09003
Author(s):  
Benaïssa Malek ◽  
Catherine Mabru ◽  
Michel Chaussumier
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Internal Pressure ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Mean Stress ◽  
Research Project ◽  
Pressure Tests

The purpose of the present research project is to study multiaxial fatigue behavior of 2618 alloy. The influence of mean stress on the fatigue behavior under tension and torsion is particularly investigated. Fatigue tests under combined tensile-torsion, in or out of phase, as well as combined tensile-torsion-internal pressure tests have also been conducted. Multiaxial fatigue results are analyzed according to Fatemi-Socie criterion to predict the fatigue life.

Relationship Between Fatigue Life Distribution, Notch Configuration, and S-N Curve of a 2024-T4 Aluminum Alloy

1985 ◽  
Vol 107 (3) ◽  
pp. 214-220 ◽  
Author(s):  
T. Shimokawa ◽  
Y. Hamaguchi
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Stress Amplitude ◽  
Fatigue Tests ◽  
Test Results ◽  
Notched Specimens ◽  
Wide Range ◽  
Life Distributions ◽  
The Relationship ◽  
Test Stress

The objective of this study is to identify the most closely related variable to the distribution of fatigue life in unnotched and three kinds of notched 2024-T4 aluminum alloy specimens. Carefully designed fatigue tests under a constant temperature and humidity condition provided fatigue life distributions over a wide range of stress amplitude. This study used about 1000 specimens. On the basis of the test results, the dependence of the scatter in fatigue life on notch configuration, the period to crack initiation, the level of stress amplitude, the median fatigue life, and the slope of the median S-N curve is investigated, and the relationship between the distributional form of fatigue life and the shape of the median S-N curve is discussed. It is concluded that the slope and shape of the median S-N curve in the vicinity of the test stress level are closely related to the scatter and distributional form of fatigue life respectively. This is common to the unnotched and three kinds of notched specimens. A variability hypothesis to correlate the median S-N curve with fatigue life distributions is examined.

Effect of Mean Stress on 2A12-T4 Aluminum Alloy under Tension-Torsion Constant Amplitude Loading

2016 ◽  
Vol 713 ◽  
pp. 334-337
Author(s):  
Tian Qing Liu ◽  
Xin Hong Shi ◽  
Jian Yu Zhang
Keyword(s):  
Shear Stress ◽  
Aluminum Alloy ◽  
Fatigue Life ◽  
Phase Angle ◽  
Stress Amplitude ◽  
Maximum Shear Stress ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Normal Mean ◽  
Fracture Appearance

Fatigue tests have been carried out to investigate the effects of mean-stress and phase-difference on the tension-torsion fatigue failure of 2A12-T4 aluminum alloy. The results show that for fully reversed tension-torsion loading, the fatigue life increases with the increase of phase angle, but the fatigue life decreases with the increase of phase angle, when mean-stress exists, both for shear mean-stress and normal mean-stress. Fracture appearance shows that the crack initiation is on the direction of maximum shear stress amplitude plane. Critical plane criteria based on the linear combination of the maximum shear stress amplitude and maximum normal stress are studied and further discussion on the drawbacks of this kind of criteria are performed.

High Temperature Low Cycle Fatigue of Superalloys Inconel 713LC and Inconel 792-5A

2007 ◽  
Vol 348-349 ◽  
pp. 101-104 ◽  
Author(s):  
Martin Petrenec ◽  
Karel Obrtlík ◽  
Jaroslav Polák
Keyword(s):  
Fatigue Life ◽  
Volume Fraction ◽  
Low Cycle Fatigue ◽  
Structural Parameters ◽  
Cyclic Hardening ◽  
Cyclic Stress ◽  
Plastic Strain Amplitude ◽  
Nickel Base Superalloy ◽  
Polycrystalline Nickel ◽  
Stress Strain

Cylindrical specimens of cast polycrystalline nickel base superalloy Inconel 713 LC and Inconel 792-5A were cyclically strained under total strain control at 23 and 700 °C. Morphology and volume fraction of γ´ precipitates are different in both materials. Cyclic hardening/softening curves, cyclic stress-strain curves, and fatigue life curves were obtained at both temperatures. The cyclic hardening/softening curves depend both on temperature and plastic strain amplitude. The cyclic stressstrain curves can be fitted by power law. Experimental data of fatigue life curves can be approximated by the Manson-Coffin and Basquin laws. Dislocation structure was studied in transmission electron microscope. Planar dislocation arrangements in the form of bands parallel to {111} planes were identified in both superalloys at both temperatures. Stress-strain response and fatigue life characteristics are compared at both temperatures and discussed in relation to dislocation arrangement and structural parameters of the materials studied.

Low-Cycle Fatigue Behavior of Small Slice Specimens of Zircaloy-4 at Elevated Temperature

2006 ◽  
Vol 324-325 ◽  
pp. 1241-1244 ◽  
Author(s):  
Li Xun Cai ◽  
Yu Ming Ye
Keyword(s):  
Elevated Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cyclic Hardening ◽  
Cyclic Softening ◽  
Fatigue Tests ◽  
Uniaxial Strain ◽  
Transverse Strain ◽  
Test Results ◽  
Element Analysis

A series of strain fatigue tests were carried out on small bugle-like slice-specimens of Zr-4 alloy at 20 and 400. According to Elastic and Plastic Finite Element Analysis and assumption of local damage equivalence, a strain formula was given to transform transverse strain of the specimen to uniaxial strain. Based on the test results of the alloy and the strain transform formula, M-C (Manson-Coffin) models to be used for estimating uniaxial fatigue life of Zr-4 alloy were obtained. The results show that, the alloy mainly behaves as cyclic softening at 20 and as cyclic hardening at 400, and the elevated temperature can lead serious additional fatigue damage of the alloy and the effect of the elevated temperature impairs gradually with increasing of amplitude strain. A conclusion is helpful that prediction life by using M-C model based on traditional strain transform equation is quite conservative when uniaxial strain amplitude is less than 0.5%.

Fatigue Characteristic and Dislocation Substructure of A356 Casting Alloy under Multi-Axial Cyclic Loadings

2011 ◽  
Vol 306-307 ◽  
pp. 489-495 ◽  
Author(s):  
De Feng Mo ◽  
Guo Qiu He ◽  
Da Fu Liu ◽  
Zheng Yu Zhu
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
Low Cycle Fatigue ◽  
Cyclic Hardening ◽  
Fatigue Tests ◽  
Loading Path ◽  
Loading Paths ◽  
Casting Alloys ◽  
The Difference ◽  
Additional Hardening

Mechanical fatigue tests were conducted on specimens of A356-T6 casting alloys under multi-axial cyclic loadings with 5 loading paths (proportional, circular, square, diamond, and ellipse path). Optical microscopy and TEM were used to examine both undeformed and fatigue failure specimens. It is shown that undeformed material has coarse microstructure with low density of dislocation. Under every loading path, cyclic hardening dominates the whole fatigue process. Additional hardening is found in this casting material, but the rate and extent of cyclic hardening and additional hardening are quite dependent on particular loading paths. Various dislocation substructures are observed in the specimens including specimens fatigued to 20 cycles and fatigue failure specimens. While these dislocation substructures are determined by the moving ability of dislocation and interactions between dislocation and particles. Low cycle fatigue life is sensitive to the difference of loading paths, and the fatigue life increases as the extent of cyclic hardening decreases.

Cyclic Softening of Cu-Ni-Si Alloy Single Crystals under Low-Cycle Fatigue

2010 ◽  
Vol 654-656 ◽  
pp. 1287-1290 ◽  
Author(s):  
Toshiyuki Fujii ◽  
Hiroshi Kamio ◽  
Yoshifumi Sugisawa ◽  
Susumu Onaka ◽  
Masaharu Kato
Keyword(s):  
Plastic Strain ◽  
Single Crystals ◽  
Low Cycle Fatigue ◽  
Strain Curve ◽  
Electron Microscopic Observation ◽  
Cyclic Hardening ◽  
Cyclic Stress ◽  
Cyclic Softening ◽  
Fatigue Tests ◽  
Electron Microscopic

Cu-2.2wt%Ni-0.5wt%Si alloy single crystals were grown by the Bridgman method and aged at 723 K for 10 h to form Ni2Si precipitates. Fully reversed tension-compression fatigue tests were conducted on the aged single crystals with a single slip orientation under constant plastic-strain amplitudes at room temperature. Cyclic softening occurred at plastic-strain amplitudes between 2.5x10-4 and 2.5x10-2. Using the maximum stress amplitude in each cyclic hardening/softening curve, a pseudo cyclic stress-strain curve (CSSC) was obtained. The CSSC was found to exhibit a plateau region with a stress level of about 167 MPa. Transmission electron microscopic observation revealed the formation of persistent slip bands (PSBs) in the plateau regime. It was found that the Ni2Si precipitate particles were intensively sheared by glide dislocations within the PSBs and were eventually re-dissolved into the Cu matrix. The macroscopic cyclic softening can be attributed to the local softening induced by the re-dissolution of the Ni2Si particles in the PSBs.

Effect of Pre-Deformation on the Cyclic Behavior and Fatigue of 304L SS

2016 ◽  
Vol 703 ◽  
pp. 125-131 ◽  
Author(s):  
Lakhdar Taleb ◽  
Crescent Kpodekon
Keyword(s):  
Fatigue Life ◽  
Cyclic Strain ◽  
Cyclic Hardening ◽  
Cyclic Softening ◽  
Fatigue Tests ◽  
Cyclic Behavior ◽  
304L Stainless Steel ◽  
Strain Control ◽  
Hardening Process ◽  
Second Category

This study deals with the effect of the loading history on the cyclic behavior and the fatigue life of a 304L stainless steel at room temperature. The experiments have been performed using two specimens’ categories. The first one (virgin) has been submitted to only classical fatigue tests while in the second category, prior to the fatigue test; the specimen was subjected to a pre-hardening process under either monotonic or cyclic strain control. Cyclic softening followed by cyclic hardening are observed for the virgin specimens while only cyclic softening is exhibited by the pre-hardened specimens. The obtained results show that fatigue life is strongly influenced by the pre-hardening: the latter seems beneficial under stress control but detrimental under strain control, even in the presence of a compressive mean stress. The results are discussed regarding the cyclic evolution of the elastic modulus as well as the isotropic and kinematic parts of the strain hardening in different configurations: with or without pre-hardening, stress or strain control.

Low-Cycle Fatigue of Nickel-Based Superalloy Hastelloy X at Elevated Temperatures

2001 ◽  
Author(s):  
Lijia Chen ◽  
Peter K. Liaw ◽  
Robert L. McDaniels ◽  
James W. Blust ◽  
Paul F. Browning ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Stress Relaxation ◽  
Test Temperature ◽  
Low Cycle Fatigue ◽  
Hold Time ◽  
Cyclic Hardening ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Hastelloy X ◽  
Nickel Based Superalloy

The fully-reversed total strain-controlled low-cycle fatigue tests with and without hold times, as well as stress-relaxation tests, were conducted at 816°C and 927°C in laboratory air on a nickel-based superalloy, HASTELLOY X. The influence of temperatures and hold times on low-cycle fatigue behavior of the alloy was investigated. At both temperatures of 816°C and 927°C, the alloy exhibited initial cyclic hardening, followed by a saturated cyclic stress response or cyclic softening under low-cycle fatigue without hold times. For low-cycle fatigue tests with hold times, however, the alloy showed either cyclic hardening or cyclic stability, which is closely related to the test temperature and the duration of the hold time. It was also observed that the low-cycle fatigue life of the alloy considerably decreased due to the introduction of strain hold times. Generally, a longer hold time would result in a greater reduction in the fatigue life. However, for the tests without hold times, the test temperature seems to have little influence on the fatigue life of the alloy at the test temperatures used in this investigation. The stress relaxation tests show that at the beginning of strain hold, the stress drops very quickly and then decreases very slowly with prolonging time. In addition, the fracture surfaces of the fatigued specimens were observed using scanning electron microscopy to determine the crack initiation and propagation modes. The fatigue life was predicted by the frequency modified tensile hysteresis energy method. The predicted lives were found to be in good agreement with the experiment results.

High-Strain Multiaxial Fatigue

1982 ◽  
Vol 104 (3) ◽  
pp. 165-173 ◽  
Author(s):  
F. Ellyin ◽  
B. Valaire
Keyword(s):  
Fatigue Life ◽  
High Strain ◽  
Low Cycle Fatigue ◽  
Fatigue Tests ◽  
Medium Carbon Steel ◽  
Multiaxial Fatigue ◽  
Cycle Fatigue ◽  
Medium Carbon ◽  
Plastic Components ◽  
Principal Strains

The aim of this investigation was to develop a method for the prediction of the high-strain multiaxial fatigue life (low-cycle fatigue) of a steel, based on high-strain uniaxial fatigue data. In this study, thinwalled cylindrical specimens were subjected to fully reversed high biaxial strains using differential pressure and axial load. The directions of the principal strains were maintained parallel and perpendicular to the specimen axes. Five different strain ratios were investigated covering both the inphase and fully out-of-phase conditions. The material selected for this investigation was a medium carbon steel; C-1018. It was found that a maximum principal strain theory, based on the plastic components of the applied strains, taking into account the strain in the thickness direction, resulted in a correlation between the biaxial and uniaxial results which was either good or conservative. Under inphase conditions the low-cycle fatigue life could be predicted using Nf = Nf0 a(ε1+ε2) and under fully out-of-phase conditions using Nf = Nf0 aε1 where ε1 and ε2 are the ordered applied plastic strains and the constants “Nf0” and “a” are obtained from uniaxial high-strain fatigue tests.

Sign in / Sign up

Export Citation Format

Share Document