The Effects of Different Architectures on Thermal Fatigue in Particle Reinforced MMC for Heat Sink Applications

Schöbel, M.; Fiedler, G.; Degischer, H. P.; Altendorfer, W.; Vaucher, S.

doi:10.4028/www.scientific.net/amr.59.177

Cited by 4 publications

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“…where T and T m denote the temperature of consideration and the solidification temperature of the matrix, respectively, a designates the coefficient of thermal expansion with the index indicating the respective phase, and V m is the matrix volume fraction. The shrinkage porosity is thus estimated to be in the order of 0.5 vol pct, in reasonable agreement with tomography measurements on a comparable Al/diamond composite [17]. Such a level of shrinkage porosity would lead to an underestimation of the particle volume fraction in the order of 3 vol pct.…”

Section: Discussionsupporting

confidence: 82%

Influence of processing route on electrical and thermal conductivity of Al/SiC composites with bimodal particle distribution

2009

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Al/SiC composites with volume fractions of SiC between 0.55 and 0.71 were made from identical tapped and vibrated powder preforms by squeeze casting (SC) and by two different setups for gas pressure infiltration (GPI), one that allows short (1-2 min) liquid metal/ ceramic contact time (fast GPI) and the other that operates with rather long contact time, i.e., 10-15 min, (slow GPI). Increased liquid metal-ceramic contact time is shown to be the key parameter for the resulting thermal and electrical conductivity in the Al/SiC composites for a given preform. While for the squeeze cast samples neither dissolution of the SiC nor formation of Al 4 C 3 was observed, the gas pressure assisted infiltration led inevitably to a reduced electrical and thermal conductivity of the matrix due to partial decomposition of SiC leading to Si in the matrix. Concomitantly, formation of Al 4 C 3 at the interface was observed in both sets of gas pressure infiltrated samples. Longer contact times lead to much higher levels of Si in the matrix and to more Al 4 C 3 formation at the interface. The difference in thermal conductivity between the SC samples and the fast GPI samples could be rationalized by the reduced matrix thermal conductivity only. On the other hand, in order to rationalize the thermal conductivity of the slow GPI a reduction in the metal/ceramic interface thermal conductance due to excessive Al 4 C 3 -formation had to be invoked. The CTE of the composites generally tended to decrease with increasing volume fraction of SiC except for the samples in which a large expansive drift was observed during the CTE measurement by thermal cycles. Such drift was essentially observed in the SC samples with high volume fraction of SiC while it was much smaller for the GPI samples. G. Sinicco-formerly an undergraduate student of É cole Polytechnique Fédérale de Lausanne, EPFL.

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Section: Discussionsupporting

confidence: 82%

Influence of processing route on electrical and thermal conductivity of Al/SiC composites with bimodal particle distribution

2009

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“…High resolution insitu synchrotron tomography is used to investigate delamination and void kinetics producing thermal fatigue damage. Pure Al as well as AlSi7 matrix composites with different particle size distributions were tested and the effects on reinforcement architectures described in [8] could be revealed.…”

Section: Introductionmentioning

confidence: 99%

Internal stresses and voids in SiC particle reinforced aluminum composites for heat sink applications

Schöbel

Altendorfer

Degischer

et al. 2011

Composites Science and Technology

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Please cite this article as: Schöbel, M., Altendorfer, W., Degischer, H.P., Vaucher, S., Buslaps, T., Di Michiel, M., Hofmann, M., Internal stresses and voids in SiC particle reinforced aluminum composites for heat sink applications, Composites Science and Technology (2011), doi: 10.1016/j.compscitech.2011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. of 19Internal stresses and voids in SiC particle reinforced aluminum composites for heat sink applications of 19 AbstractMetal matrix composites (MMC) are being developed for power electronic IGBT modules, where the heat generated by the high power densities has to be dissipated from the chips into a heat sink. As a means of increasing long term stability a base plate material is needed with a good thermal conductivity (TC) combined with a low coefficient of thermal expansion (CTE) matching the ceramic insulator. SiC particle reinforced aluminum (AlSiC) offers the high TC of a metal with the low CTE of a ceramic. Internal stresses are generated at the matrix-particle interfaces due to the CTE mismatch between the constituents of the MMC during changing temperatures. Neutron and synchrotron diffraction was performed to evaluate the micro stresses during thermal cycling. The changes in void volume fraction, caused by plastic matrix deformation, are visualized by synchrotron tomography. The silicon content in the matrix connecting the particles to a network of hybrid reinforcement contributes essentially to the long term stability by an interpenetrating composite architecture.

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Reinforcement architectures and thermal fatigue in diamond particle-reinforced aluminum

et al. 2010

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The Effects of Different Architectures on Thermal Fatigue in Particle Reinforced MMC for Heat Sink Applications

Cited by 4 publications

References 1 publication

Influence of processing route on electrical and thermal conductivity of Al/SiC composites with bimodal particle distribution

Influence of processing route on electrical and thermal conductivity of Al/SiC composites with bimodal particle distribution

Internal stresses and voids in SiC particle reinforced aluminum composites for heat sink applications

Reinforcement architectures and thermal fatigue in diamond particle-reinforced aluminum

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