Low-cycle fatigue of friction stir welded Al–Mg alloys

Czechowski, M.

doi:10.1016/j.jmatprotec.2005.02.078

Cited by 62 publications

(50 citation statements)

References 1 publication

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“…16) In the past decade, a number of studies have been undertaken to characterize the microstructural evolution resulting from friction stir processing, 2,17,18) but there is still a lack of vibration fracture data due to this being a relatively new process. A previous study pointed out 19) that as-stirred Al-Mg alloy can effectively lengthen the fatigue life compared to the traditional joining method. In our previous investigation on the resonant vibration of Al-Mg alloy, 7,20) it was found that grain refinement is able to improve the crack propagation resistance.…”

Section: Introductionmentioning

confidence: 99%

Effect of Dynamically Recrystallized Grain Size on the Tensile Properties and Vibration Fracture Resistance of Friction Stirred 5052 Alloy

2006

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5052H34 Al-Mg plates were annealed and then friction stir processed at various rotation speeds ranging from 500 to 1500 rpm to investigate the tensile properties and vibration fracture resistance. The experimental results indicate that grain refinement could be observed at the stir zone with an average grain size varying from 5-16 mm. Based on the observed microstructure and tensile deformation resistance data, the k y slope value of the Hall-Petch equation can be determined. A refined grain size in the stir zone is a common feature of the friction stirred specimens. Different rotation speeds have different corresponding grain sizes and this can be attributed to dynamic recrystallization during friction stir processing (FSP). The effect of grain size on vibration fracture resistance in the stir zone was also examined. Results show that the vibration fracture resistance of the stir zone decreases with increasing the rotation speed. An increase in grain size due to higher rotation speed is detrimental to the vibration propagation resistance, and a small variation in grain size can result in significant changes in the duration of stage I of the D-N curves. The inward crack propagation behavior was found to be the main controlling factor on vibration fracture resistance. This result agrees with the variation in crack propagation rate.

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Section: Introductionmentioning

confidence: 99%

Effect of Dynamically Recrystallized Grain Size on the Tensile Properties and Vibration Fracture Resistance of Friction Stirred 5052 Alloy

2006

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“…These identifications were confirmed with energy-dispersive spectroscopy (EDS) in a scanning electron microscope (SEM), JEOL* JSM 5610 SEM with an Oxford INCA200 EDS detector (Oxford Instruments, Abingdon, Oxfordshire, UK). Note that the specific stoichiometry of the Mg-Si intermetallic particles was not determined in this study, but other investigators have most commonly observed Mg 2 Si, [37][38][39] with some reports of more complex chemistries. [40,41] IV.…”

Section: Methodsmentioning

confidence: 88%

Effect of Microstructure on Cavitation during Hot Deformation of a Fine-Grained Aluminum-Magnesium Alloy as Revealed through Three-Dimensional Characterization

Chang

Taleff

Krajewski

2009

Metall Mater Trans A

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The effect of microstructure on cavitation developed during hot deformation of a fine-grained AA5083 aluminum-magnesium alloy is investigated. Two-point correlation functions and threedimensional (3-D) microstructure characterization reveal that cavitation depends strongly on the mechanism that controls plastic deformation. Grain-boundary-sliding (GBS) creep produces large, interconnected cavities rapidly during plastic straining. Solute-drag (SD) creep produces isolated cavities with less total volume fraction at a given strain. The 3-D microstructure data reveal adjacency between various microstructural features. Cavities are observed to be preferentially adjacent to large Al 6 (Mn,Fe) particles and to Mg-Si particles of all observed sizes. These data suggest that cavities preferentially nucleate at Mg-Si particles and at large Al 6 (Mn,Fe) particles. This result may be applied to reduce cavitation in commercial hot-forming operations utilizing aluminum-magnesium alloys.

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“…8,9) In particular, Al-2.5Mg alloys have already been used in transportation systems which can experience abnormal vibrations, and hence severe fracture problems occur when the applied vibration frequency meets the resonance. 10,11) Our previous report 12) confirmed that the Al-Mg alloy can acquire better mechanical properties after friction stirring. In addition, previous reports have pointed out [13][14][15] the higher densities of dislocations and grain boundaries introduced by pre-strain can raise the strength and the ability for absorbing the vibration energy, and consequently improve the crack propagation resistance of Al-Mg alloys.…”

Section: Introductionmentioning

confidence: 79%

Effect of Prior Deformation on Tensile and Vibration Fracture Resistance of Friction Stirred 5052 Alloy

2006

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In this study, Al-2.5Mg alloy was prepared with different cold rolling reductions, and then friction stir processing (FSP) was performed to investigate the effect of prior microstructure variations on friction stirred materials. The experimental results indicate that the FSP specimens not only had better tensile properties but also better vibration fracture resistance, which would be expected from the microstructural refinement which resulted from the phenomenon of dynamic recrystallization. The stress-elongation curves of all specimens showed the serrated yielding. The higher grain boundary introduced by FSP could hold the mobile dislocations long enough to let Mg atoms form atmospheres around them. Consequently, the effect serration magnitude was more significant on the specimens which were given FSP. This can be ascribed to the grain refinement and the resulting increase of the boundaries which is the main source of obstacles. In addition, the vibration fracture resistance of the FSP specimens shows that the duration of stage I decreases with increasing the prior deformation rate before FSP.Meanwhile, the prior deformation samples possessed better vibration fracture resistance under the same initial deflection amplitude (6.5 mm). Based on the observed microstructures, this can be attributed to a large number of retained dislocation tangles introduced by prior cold rolling, even after FSP, which improved the crack propagation resistance and reduced the crack propagation rate. The experimental results confirmed that vibration fracture resistance can be quantitatively correlated with the crack tortuosity value which corresponds to the crack propagation behavior.

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Low-cycle fatigue of friction stir welded Al–Mg alloys

Cited by 62 publications

References 1 publication

Effect of Dynamically Recrystallized Grain Size on the Tensile Properties and Vibration Fracture Resistance of Friction Stirred 5052 Alloy

Effect of Dynamically Recrystallized Grain Size on the Tensile Properties and Vibration Fracture Resistance of Friction Stirred 5052 Alloy

Effect of Microstructure on Cavitation during Hot Deformation of a Fine-Grained Aluminum-Magnesium Alloy as Revealed through Three-Dimensional Characterization

Effect of Prior Deformation on Tensile and Vibration Fracture Resistance of Friction Stirred 5052 Alloy

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