Multiaxial cyclic behaviour of extruded and forged AZ80 Mg alloy

Gryguc, Andrew; Behravesh, Seyed Behzad; Shaha, S.K.; Jahed, Hamid; Wells, Mary A.; Williams, Bruce W.; Su, Xuming

doi:10.1016/j.ijfatigue.2019.06.015

Cited by 45 publications

(26 citation statements)

References 41 publications

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“…Fig. 4 illustrates the macroscopic morphology of the fracture surface and topological features with roughness assessment using quantitative LOM for a laboratory fatigue test specimen with geometry as per Gryguć et al [21]. This specimen was extracted from location #8 within the forged component which was free from these aforementioned macroscopic cold-shut/poor fusion defects, and then subsequently underwent fully reversed strain-controlled fatigue testing with a strain amplitude of ε A = 0.8% and failed at 568 cycles.…”

Section: Fracture Behaviour In Laboratory Test-specimens Under Fully mentioning

confidence: 99%

“…7). Although the two Mg alloys are different (AZ80 vs. ZK60), their defect free fatigue properties are very similar (for the processing conditions of these two forgings which were both 300°C and a rate of 2.1 -4.2 mm/sec) [21,22,36]. The component with a lower forging defect intensity exhibited almost a 4.5x longer life than the one with a higher defect intensity.…”

Section: Fracture Behaviour In Full-scale Component Under Representatmentioning

confidence: 99%

“…Characterization of the as-forged properties of forged Mg components in recent years has become T more widespread in literature. Many studies have focused on characterization of the monotonic structural properties of forged AZ80 and ZK60 Mg, in open die forgings [3][4][5] as well as for closed die forged components such as wheels [6][7][8], aerospace components [5,[8][9][10][11][12], and finally, automotive structural components [13][14][15][16][17][18][19][20][21][22][23][24]. In general, the main focus of these studies was the feasibility of achieving adequate material flow to produce the desired forged shape, whilst characterizing the resulting microstructure and quasi-static material properties.…”

Section: Introductionmentioning

confidence: 99%

“…Matsumoto et al conducted forging combined with backwards extrusion of ZK60 Mg to produce simple components with small rib features and found that ZK60 has a high propensity for the surface to oxidize at temperatures greater than 400°C, and shear cracks would develop at temperatures below 200°C, however at 300°C they were able to forge a component which was free of macroscopic defects. Several recent works by Gryguć et al have investigated varying the processing parameters of Mg forging with the specific objective of improving the strength, fatigue performance, and improving the homogeneity of properties throughout the forging [3,4,[19][20][21][22][23][25][26][27]. Despite this, there has been little to no work done on developing a link between the fatigue response and nature of the failure morphology to the forging defects present in an Mg component produced via an industrially representative forging process.…”

Section: Introductionmentioning

confidence: 99%

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Effect of thermomechanical processing defects on fatigue and fracture behaviour of forged magnesium

Gryguc

Behravesh

Jahed

et al. 2020

Frattura Ed Integrità Strutturale

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The microstructural origins of premature fatigue failures were investigated on a variety of forged components manufactured from AZ80 and ZK60 magnesium, both at the test specimen level and the full-scale component level. Both stress and strain-controlled approaches were used to characterize the macroscopically defect-free forged material behaviour as well as with varying levels of defect intensities. The effect of thermomechanical processing defects due to forging of a industrially relevant full-scale component were characterized and quantified using a variety of techniques. The fracture initiation and early crack growth behaviour was deterministically traced back to a combination of various effects having both geometric and microstructural origins, including poor fusion during forging, entrainment of contaminants sub-surface, as well as other inhomogeneities in the thermomechanical processing history. At the test specimen level, the fracture behaviour under both stress and strain controlled uniaxial loading was characterized for forged AZ80 Mg and a structure-property relationship was developed. The fracture surface morphology was quantitatively assessed revealing key features which characterize the presence and severity of intrinsic forging defects. A significant degradation in fatigue performance was observed as a result of forging defects accelerating fracture initiation and early crack growth, up to 6 times reduction in life (relative to the defect free material) under constant amplitude fully reversed fatigue loading. At the full-scale component level, the fatigue and fracture behaviour under combined structural loading was also characterized for a number of ZK60 forged components with varying levels of intrinsic thermomechanical processing defects. A novel in-situ non-contact approach (utilizing Digital-Image Correlation) was used as a screening test to establish the presence of these intrinsic defects and reliably predict their effect on the final fracture behaviour in an accelerated manner compared to conventional methods.

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Section: Fracture Behaviour In Laboratory Test-specimens Under Fully mentioning

confidence: 99%

Section: Fracture Behaviour In Full-scale Component Under Representatmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of thermomechanical processing defects on fatigue and fracture behaviour of forged magnesium

Gryguc

Behravesh

Jahed

et al. 2020

Frattura Ed Integrità Strutturale

Self Cite

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“…Dey et al used an elastic solution, even though they applied relatively high strain values [31]. There are also several papers where the shear stress determination method was not mentioned [32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

The Shear Stress Determination in Tubular Specimens under Torsion in the Elastic–Plastic Strain Range from the Perspective of Fatigue Analysis

2020

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The comparison of shear stress determination methods in tubular specimens under torsion is presented in this paper. Four methods were analyzed: purely elastic solutions, purely plastic solutions, the midsection approach, and the Chaboche nonlinear kinematic hardening model. Using experimental data from self-designed and conducted fatigue experiments, an interesting insight on this problem was obtained that is not often tackled in the literature. It was shown that there are differences in determined shear stress values, and their level depends on a few factors. The midsection approach and purely plastic solution gave values of surface shear stress very close to the values obtained using the Chaboche nonlinear kinematic hardening model for high strain levels. The purely elastic solution gave proper results for the low strain ranges, close to the cyclic yield limit. Since none of the methods can be trusted in the full range of loading, an important conclusion from these analyses regards the formulated ranges of their applicability. It was also shown that the calculated values of shear stress and plastic and elastic strain energy density determined on this basis have a strong impact on fatigue life predictions. Finally, the influence of predicted values of shear stresses on the interpretation of cyclic hardening phenomena was also presented.

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Hot Deformation Behavior and Constitutive Model of AZ80–0.8wt%Y Considering the Compensation of Strain

Wang

et al. 2021

Adv Eng Mater

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To evaluate the hot flow behavior of homogenized AZ80 magnesium alloy containing 0.8 wt% yttrium, isothermal hot compression tests are conducted among the different temperature ranges of 340–420 °C under the strain rates of 10−2–101 s−1 by using a Gleeble‐3800 thermo‐simulator. The flow stress variation of high temperature and strain rate on the microstructure is analyzed. In the constitutive equation for the AZ80‐0.8wt%Y, it is conducive to obtain the deformation activation energy and the change law of strain of the material constant through the relationship between peak stress, deformation temperature, and strain rate. The deformation activation energy is found to be about 119.03 kJ mol−1. Subsequently, the values of the correlation coefficient (R) and the average absolute relative error (AARE) are 0.9826 and 7.29%, respectively. Consequently, the results indicate that the strain‐dependent constitutive equation has a good agreement with the calculated and measured flow stresses in the elevated temperature range for the AZ80–0.8wt%Y.

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Multiaxial cyclic behaviour of extruded and forged AZ80 Mg alloy

Cited by 45 publications

References 41 publications

Effect of thermomechanical processing defects on fatigue and fracture behaviour of forged magnesium

Effect of thermomechanical processing defects on fatigue and fracture behaviour of forged magnesium

The Shear Stress Determination in Tubular Specimens under Torsion in the Elastic–Plastic Strain Range from the Perspective of Fatigue Analysis

Hot Deformation Behavior and Constitutive Model of AZ80–0.8wt%Y Considering the Compensation of Strain

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