In situ investigation of strain heterogeneity and microstructural shear bands in rolled Magnesium AZ31

Üçel, I. B.; Kapan, Enver; Türkoğlu, Olcay; Aydıner, C. Can

doi:10.1016/j.ijplas.2019.02.008

Cited by 28 publications

(9 citation statements)

References 50 publications

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“…It has been used interchangeably with SB as both reflect the damage of material localization 57 . SB is formed under large shear deformation such as equal‐channel angular pressing of aluminum alloy, biaxial loaded NiTi, and cold rolling of high‐entropy alloys 58–60 . Elibol and Wagner 61 studied the localization of shear stress‐driven deformation under static compression.…”

Section: Discussionmentioning

confidence: 99%

White etching area damage induced by shear localization in rolling contact fatigue of bearing steel

Chen,

Xie,

et al. 2023

Fatigue Fract Eng Mat Struct

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White etching area (WEA) is a primary damage in rolling contact fatigue (RCF) of bearing steels. In spite of extensive investigations, there is a large discrepancy in the existing mechanisms of WEA formation. We attempt to unify the mechanisms from the perspective of shear localization and plastic damage accumulation based on ductile damage. RCF tests were conducted to generate WEAs with various microstructures and compositions. A thermodynamically consistent model of the ductile damage evolution from an inclusion was established by developing the phase field damage coupled with the crystal elastic‐viscoplastic constitutive relationship under RCF. The model was implemented into the FE framework through a user materials subroutine. The results indicated that the WEA is the shear band resulting from shear localization. The large inhomogeneity and scatter in WEA's microstructure are due to the influence of the crystal orientation. The development and orientation of SBs predicted by the model and the experimental observation of the WEA are in good agreement. The large micro‐shear strain in the WEA provides the driving force for mechanically controlled austenite phase transformation. The shear band center, which has the largest strain and the least stress, is where cracks initiate. This demonstrates that contrary to earlier reports that WEA is induced by previously formed crack faces friction, cracks actually initiate from the interior of the WEA.

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Section: Discussionmentioning

confidence: 99%

White etching area damage induced by shear localization in rolling contact fatigue of bearing steel

Chen,

Xie,

et al. 2023

Fatigue Fract Eng Mat Struct

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“…In a similar study by Xia et al [36] with Mg-AZ31 at RT, particular attention was paid to inhomogeneous strain fields, which cause the distortion of grains. In Reference [37], shear bands in AZ31, as well as in pure magnesium [38], are seen to be activated early and incur heavy local strains. As soon as GBS occurs, the grain boundaries, which are dimensionally like the EBSD initial state analysis, become clearly visible.…”

Section: Deformation Mechanismsmentioning

confidence: 99%

GTN Model-Based Material Parameters of AZ31 Magnesium Sheet at Various Temperatures by Means of SEM In-Situ Testing

et al. 2020

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Magnesium alloys are primarily associated with complex forming mechanisms, which yield ductility at high temperatures. In sheet metal forming, high triaxiality stress states that favor the ductile damage mechanisms of void formation and growth are known to malleable metals. The formulation of coupled damage models has so far failed, due to the incomplete experimental determination of damage parameters for magnesium AZ31 thin sheet. A quantitative investigation was conducted to determine the ductile damage behavior of twin-roll cast, hot rolled, and annealed AZ31 thin sheet. Results on the mechanisms of void nucleation-, coalescence- and growth-rate were established at temperatures ranging from room temperature to 350 °C. In-situ tensile tests were carried out in a scanning electron microscope with three different specimen types: Simple tension specimens, notched specimens for high triaxiality stress state testing, and shear specimens. Through a comparative analysis of local strains measured by digital image correlation and local void volume fractions determined through post-mortem analysis of specimen cross-sections, GTN (Gurson–Tvergaard–Needleman) model-based material parameters were determined by experiment, representing a novel departure in the magnesium research landscape. The procedure developed in this context should also be transferable to other metals in the form of thin sheets.

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“…The formation of deform bands during the plastic forming of the as-rolled Mg alloy sheets has been reported in many studies. The possible formation mechanisms of these deform bands have been proposed to be related to twinning-induced shear banding (TISB) [32,33] and weak texture-induced shear banding (WTISB) [34][35][36]. The boundaries of SNL are highlighted by the red dotted lines, as shown in Figure 3a,e.…”

Section: Microstructure Evolution During Bendingmentioning

confidence: 99%

Unusual Spreading of Strain Neutral Layer in AZ31 Magnesium Alloy Sheet during Bending

Liu

Bai

et al. 2022

Materials

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In this work, we reported an unusual phenomenon of strain neutral layer (SNL) spreading in an as-rolled AZ31B magnesium alloy sheet during V-bending. The SNL on the middle symmetrical surface perpendicular to the transverse direction (TD) of the sheet extended to the compression region and was accompanied by a mound-like feature. However, the SNL on the side surface perpendicular to the TD was distributed with a parallel band feature. The underlying mechanism was revealed by the finite element (FE) analysis. The results indicate that the three-dimensional compressive stresses in the compression region of the bending samples were responsible for the above phenomenon. Moreover, the area of the SNL in the middle position gradually decreased as the bending test progressed. The findings in this study provide some new insights into the bending deformation behavior of magnesium alloy.

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In situ investigation of strain heterogeneity and microstructural shear bands in rolled Magnesium AZ31

Cited by 28 publications

References 50 publications

White etching area damage induced by shear localization in rolling contact fatigue of bearing steel

White etching area damage induced by shear localization in rolling contact fatigue of bearing steel

GTN Model-Based Material Parameters of AZ31 Magnesium Sheet at Various Temperatures by Means of SEM In-Situ Testing

Unusual Spreading of Strain Neutral Layer in AZ31 Magnesium Alloy Sheet during Bending

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