Microtomographic study of the evolution of microstructure during creep of an AlSi12CuMgNi alloy reinforced with Al2O3 short fibres

Requena, Guillermo; Degischer, Peter; Marks, Esteban; Boller, Élodie

doi:10.1016/j.msea.2007.10.016

Cited by 34 publications

(30 citation statements)

References 10 publications

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“…This can be overcome by means of synchrotron tomography where the phase contrast can be exploited to resolve the eutectic Si from the Al. [10,11] Furthermore, the contrast between these two phases can be improved by means of holotomography for which a map of the electron density of the phases is obtained. [12] Taking all these facts into account, the objective of the present work is to bridge the gap between the already available results that make use of 2D methodologies to characterize the binary AlSi12 system (see e.g.…”

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confidence: 99%

3D Architecture and Load Partition in Eutectic Al‐Si Alloys

et al. 2009

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The changes of the three dimensional architecture of a eutectic AlSi12 alloy during heat treatment are revealed by means of synchrotron holotomography. The non‐destructive nature of the holotomography technique allows to analyze the same volumes in different thermal conditions. The results show a disintegration of the interconnected eutectic Si‐lamellae into isolated elongated particles. The load carrying capacity of both types of Si morphologies is studied by in situ neutron diffraction during compression tests. The experimental results are compared to those obtained using a micromechanical model developed for metal matrix composites based on a homogenization approach. The correlation between experiments and calculations shows that the interconnectivity of Si must be considered to account for the strength exhibited by the eutectic alloy. The present study bridges the gap between the already available two‐dimensional studies of architecture and properties of the binary AlSi12 alloy and new three‐dimensional studies of more complex systems based on this alloy.

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confidence: 99%

3D Architecture and Load Partition in Eutectic Al‐Si Alloys

et al. 2009

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“…[5] The edge enhancement resulting from the phase contrast mode produces the necessary contrast between phases having similar mass densities, as it is the case for the Al matrix and the eutectic Si, present in the investigated SFRM. Artificial fringes in the interfaces were present due to the nature of the contrast phase technique but a relative comparison between the investigated conditions was possible.…”

Section: Description Of the Materialsmentioning

confidence: 81%

“…[2][3][4] To ensure the reliability of such materials under long-term temperature/load exposure, the mechanisms controlling their thermomechanical behavior are to be known.In previous studies, [3,5] an SF reinforced AlSi12CuMgNi alloy showed a decrease in stationary creep rate with the creep exposure time extending several thousand hours at 300 8C. Microtomographic evaluations [5] revealed microstructural changes of the Si phase, specially of the interconnectivity between Si, SFs, and intermetallics.…”

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confidence: 83%

“…This was attributed to the formation of a highly interconnected 3D network of eutectic Si connecting the SFs. [3,5] The Si diffusion at 300 8C is intensified by the high number of interfaces provided by the SFs, as well as by the external load. [5] As a result the Si coalesces between the SFs.…”

Section: Description Of the Materialsmentioning

confidence: 99%

“…Microtomographic evaluations [5] revealed microstructural changes of the Si phase, specially of the interconnectivity between Si, SFs, and intermetallics.…”

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confidence: 99%

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Microtomography and Creep Modeling of a Short Fiber Reinforced Aluminum Piston Alloy

et al. 2010

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Short fiber reinforced metals (SFRMs) have shown promising mechanical properties at elevated temperature, [1] leading to applications for combustion engines where some components locally reinforced with short fibers (SFs) have been developed. [2][3][4] To ensure the reliability of such materials under long-term temperature/load exposure, the mechanisms controlling their thermomechanical behavior are to be known.In previous studies, [3,5] an SF reinforced AlSi12CuMgNi alloy showed a decrease in stationary creep rate with the creep exposure time extending several thousand hours at 300 8C. Microtomographic evaluations [5] revealed microstructural changes of the Si phase, specially of the interconnectivity between Si, SFs, and intermetallics.Models of creep behavior of SFRM have focused on the spatial arrangement of the fibers, [6] the influence of damage, [7] the work hardened zone between matrix and fibers, [8][9][10] and the constitutive creep law of the matrix material [11] but few have studied the influence of the interpenetrating architecture of the rigid phases (e.g., ref.[12]).In the present investigation a three-dimensional (3D) unit cell finite element (FE) model is proposed in order to study the influence of the 3D connectivity between Si and SFs on the creep resistance of AlSi-based SFRM. This simple model is based on 3D microstructural features and it is correlated with experimental results. Experimental

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The Effect of the Connectivity of Rigid Phases on Strength of AlSi Alloys

et al. 2011

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The load carrying capacity of the eutectic Si in AlSi alloys depends on its volume fraction, distribution, morphology and connectivity, namely its internal architecture. This can be modified by heat treatment at temperatures close to the eutectic point causing the spheroidisation and loss of connectivity of the eutectic Si. This decreases the load carrying capacity of the eutectic Si and, consequently, the room and high temperature strength of AlSi alloys is reduced. The presence of other phases such as ceramic short fibres and aluminides in AlSi alloys can result in the formation of hybrid three‐dimensional structures that strongly delay and/or suppress the morphological changes and the loss of connectivity of the eutectic Si. As a result, the thermo‐mechanical behaviour of these heterogeneous lightweight materials is improved and stable. These effects have been explored in the last years by the authors and the main results are compiled and presented in the present work with special emphasis in the relationship between the architecture and the strength of different AlSi‐based materials.

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Microtomographic study of the evolution of microstructure during creep of an AlSi12CuMgNi alloy reinforced with Al2O3 short fibres

Cited by 34 publications

References 10 publications

3D Architecture and Load Partition in Eutectic Al‐Si Alloys

3D Architecture and Load Partition in Eutectic Al‐Si Alloys

Microtomography and Creep Modeling of a Short Fiber Reinforced Aluminum Piston Alloy

The Effect of the Connectivity of Rigid Phases on Strength of AlSi Alloys

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