Microtomographic study and finite element analysis of the porosity harmfulness in a cast aluminium alloy

Vanderesse, Nicolas; Maire, Éric; Chabod, Amaury; Buffière, Jean‐Yves

doi:10.1016/j.ijfatigue.2011.06.010

Cited by 60 publications

(22 citation statements)

References 14 publications

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“…This is also sometimes coupled with a Finite Element simulation of the stresses around each pore. 218,221 Complex attributes such as the local orientation of anisotropic features (rod-or plate-like second phases in a matrix) have also been measured in metallic materials based on the so-called 'grey level texture' in the images. For this, it is necessary to calculate the gradient in the neighbourhood of each voxel.…”

Section: Inclusion/matrix Morphologiesmentioning

confidence: 99%

Quantitative X-ray tomography

Maire¹,

Withers²

2013

International Materials Reviews

1,089

601

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X-ray computer tomography (CT) is fast becoming an accepted tool within the materials science community for the acquisition of 3D images. Here the authors review the current state of the art as CT transforms from a qualitative diagnostic tool to a quantitative one. Our review considers first the image acquisition process, including the use of iterative reconstruction strategies suited to specific segmentation tasks and emerging methods that provide more insight (e.g. fast and high resolution imaging, crystallite (grain) imaging) than conventional attenuation based tomography. Methods and shortcomings of CT are examined for the quantification of 3D volumetric data to extract key topological parameters such as phase fractions, phase contiguity, and damage levels as well as density variations. As a non-destructive technique, CT is an ideal means of following structural development over time via time lapse sequences of 3D images (sometimes called 3D movies or 4D imaging). This includes information needed to optimise manufacturing processes, for example sintering or solidification, or to highlight the proclivity of specific degradation processes under service conditions, such as intergranular corrosion or fatigue crack growth. Besides the repeated application of static 3D image quantification to track such changes, digital volume correlation (DVC) and particle tracking (PT) methods are enabling the mapping of deformation in 3D over time. Finally the use of CT images is considered as the starting point for numerical modelling based on realistic microstructures, for example to predict flow through porous materials, the crystalline deformation of polycrystalline aggregates or the mechanical properties of composite materials.

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Section: Inclusion/matrix Morphologiesmentioning

confidence: 99%

Quantitative X-ray tomography

Maire¹,

Withers²

2013

International Materials Reviews

1,089

601

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“…Sun et al [31] modeled an actual microstructure based on scanning electron microscrope (SEM) image, under plane stress conditions. Vanderesse et al [32] meshed a volumetric image obtained by X-ray microtomography and carried out FE simulations. Padilla et al [33] carried out FE simulations of a microstructure obtained via X-ray microtomography in order to assess the evolution of damage in a single lap shear joint.…”

Section: Numerical Frameworkmentioning

confidence: 99%

Void growth and coalescence in a three-dimensional non-periodic void cluster

Navas

Bernacki

Bouchard

2018

International Journal of Solids and Structures

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Void growth and coalescence are studied in this work through Finite Element simulations. A methodology for the study of threedimensional non-periodic configurations is proposed. In order to avoid the hypothesis of microstructural periodicity, a three-dimensional cluster with three initially spherical voids, is modeled. Multiple spatial configurations are simulated in a parametric study. The precoalescence behavior is detailed through the evolution of the volume of each void, the minimum intervoid distance, and the equivalent plastic strain in the middle of the shortest path between voids, and the resulting coalescence mechanism is described. Locally accelerated and non-homogeneous void growth is observed close to the localization band. Although only coalescence by internal necking is present, apparent void-sheet formation is observed if only a two-dimensional slice is considered. These observations, and a comparison with the RiceTracey growth model, highlight the importance of fully considering the three-dimensional complexity of the ductile damage micromechanisms.

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“…[10][11][12]22] Some have attempted to include 3D information of the porosity distribution into models of cast alloys. [23][24][25] The 3D geometry of the pores was measured using X-ray computed tomography (XCT) techniques or by serial sectioning combined with metallographic observations. In Reference 23, a significant fraction of pores is measured and the methodology to include this fraction in a finite element (FE) mesh is described.…”

Section: Introductionmentioning

confidence: 99%

“…In Reference 24, a single pore is taken into account. Vanderesse et al [25] utilize a relatively large microstructural volume of a cast aluminum alloy as an input for FE calculations. Further work is clearly needed in this area if realistic models of HPDC Mg alloys with good predictive capability are to be developed.…”

Section: Introductionmentioning

confidence: 99%

Effect of Hydrostatic Pressure on the 3D Porosity Distribution and Mechanical Behavior of a High Pressure Die Cast Mg AZ91 Alloy

Sket

Fernández

Jérusalem

et al. 2015

Metall Mater Trans A

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A limiting factor of high pressure die cast (HPDC) Mg alloys is the presence of porosity, which has a detrimental effect on the mechanical strength and gives rise to a large variability in the ductility. The application of hydrostatic pressure after casting is known to be beneficial to improve the mechanical response of HPDC Mg alloys. In this study, a combined experimental and simulation approach has been developed in order to investigate the influence of pressurization on the 3D porosity distribution and on the mechanical behavior of an HPDC Mg AZ91 alloy. Examination of about 10,000 pores by X-ray computed microtomography allowed determining the effect of hydrostatic pressure on the bulk porosity volume fraction, as well as the change in volume and geometry of each individual pore. The evolution of the 3D porosity distribution and mechanical behavior of a sub-volume containing 200 pores was also simulated by finite element analysis. Both experiments and simulations consistently revealed a decrease in the bulk porosity fraction and a bimodal distribution of the individual volume changes after the application of the pressure. This observation is associated with pores containing internal pressure as a result of the HPDC process. Furthermore, a decrease in the complexity factor with increasing volume change is observed experimentally and predicted by simulations. The pressure-treated samples have consistently higher plastic flow strengths.

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Microtomographic study and finite element analysis of the porosity harmfulness in a cast aluminium alloy

Cited by 60 publications

References 14 publications

Quantitative X-ray tomography

Quantitative X-ray tomography

Void growth and coalescence in a three-dimensional non-periodic void cluster

Effect of Hydrostatic Pressure on the 3D Porosity Distribution and Mechanical Behavior of a High Pressure Die Cast Mg AZ91 Alloy

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