Void growth in copper during high-temperature power-law creep

Dzięcioł, Krzysztof; Borbély, András; Sket, F.; Isaac, Augusta; Michiel, Marco Di; Cloetens, Peter; Buslaps, T.; Pyzalla, A.

doi:10.1016/j.actamat.2010.10.003

Cited by 30 publications

(31 citation statements)

References 37 publications

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“…For instance, copper was tested at 50% of the melting temperature indicating that growth of voids with radii of a few microns is determined by a viscous flow mechanism. 99 By following the evolution of individual voids it was concluded that void coalescence follows two stable growth regimes involving the impingement of neighbouring primary voids, followed by the coalescence of secondary voids before final rupture. 350 For AlzAl 2 O 3 particle containing composite, there is a change in the damage mechanism with matrix delamination and matrix voiding occurring at high temperature (300uC) but particle fracture contributing at 200uC.…”

Section: Void/damage Evolutionmentioning

confidence: 99%

“…It helps quantify void nucleation and growth, 99 In the context of nanotomography the field of view is usually around 10006 the spatial resolution, which means that nanotomography is often synonymous with very small samples (see 'Local tomography and laminography' section), presenting both statistical sampling and engineering relevance issues, see 'Caveats and cautions' section.…”

Section: Very High Resolution Imagingmentioning

confidence: 99%

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Quantitative X-ray tomography

Maire¹,

Withers²

2013

International Materials Reviews

1,086

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: Void/damage Evolutionmentioning

confidence: 99%

Section: Very High Resolution Imagingmentioning

confidence: 99%

Quantitative X-ray tomography

Maire¹,

Withers²

2013

International Materials Reviews

1,086

601

View full text Add to dashboard Cite

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“…It is evident that the simulation largely underestimates the true volumetric growth, a rather surprising result since the selected cavity has an elongated shape and grows mainly along the load axis, a characteristic feature of void growth by creep flow mechanism. [9] Results of Dzieciol et al [31] indicate that the K parameter describing viscous void growth during power law creep of 99.99 pct purity copper is much higher (K % 45). In the case of copper, however, a pure proportionality between growth rate and volume was obtained, which made interpretation of void growth results rather straightforward.…”

Section: A Cavity Growth By Plastic Creep Flowmentioning

confidence: 95%

“…The existence of a void-filling mechanism in leaded brass is indirectly supported by the absence of negative growth rates in single-phase copper. [31] Since the volume fraction of lead-rich particles is small (of 2 pct), the pore filling mechanism should be marginal. This indicates, however, that the parameter K % 22 should be considered as a lower bound, because the contribution of filling mechanism to the ''positive growth rates'' is unknown.…”

Section: B Influence Of Local Cavity Surrounding On Growth Ratementioning

confidence: 99%

“…Experimentally, this can be achieved using nondestructive techniques allowing the identification and characterization of the evolution of single cavities. The investigation method partly satisfying these criteria is X-ray microtomography developed at synchrotron sources, [26] which has several advantages over the conventional techniques: (1) provides the 3-D morphology of cavities at progressive stages of creep, (2) makes visible the connectivity between cavities (voids may appear separated on 2-D sections), (3) clearly visualizes the inhomogeneity of damage distribution, [27][28][29][30][31][32] and (4) is free of specimen preparation artifacts.…”

Section: Introductionmentioning

confidence: 99%

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In-Situ Microtomographic Characterization of Single-Cavity Growth During High-Temperature Creep of Leaded Brass

Isaac

Dzięcioł

Sket

et al. 2011

Metall Mater Trans A

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International audienceSynchrotron microtomography was used for in-situ characterization of high-temperature creep damage in leaded brass. Applying image registration to subsequent tomographic reconstructions, the volumetric growth rate of single cavities with equivalent radii between 2 and 4.3 mu m was assessed. We conclude from the volume dependence of the growth rates that both the viscous flow and grain boundary (GB) diffusion mechanisms influence void growth. We show that void growth in leaded brass is retarded by negative stress triaxiality, which develops in the matrix during heating the specimen to the deformation temperature

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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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Void growth in copper during high-temperature power-law creep

Cited by 30 publications

References 37 publications

Quantitative X-ray tomography

Quantitative X-ray tomography

In-Situ Microtomographic Characterization of Single-Cavity Growth During High-Temperature Creep of Leaded Brass

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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