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

Abstract

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.

Microstructures and Tensile Properties of Al–Cu Matrix Composites Reinforced with Nano-Sized SiCp Fabricated by Semisolid Stirring Process

“…[5][6][7]. For example, SiC p reinforced AMCs are used for engine piston, and heat sink [8,9]. Compared with traditional micron-sized SiC p /Al composites, the higher tensile strength and good ductility of the nano-sized SiC p /Al composites entitle them to have more competitive ability for advanced structural applications such as in automotive and aerospace industries and the military [10].…”

Fatigue crack growth in SiC particle reinforced Al alloy matrix composites at high and low R-ratios by in situ X-ray synchrotron tomography

“…Tensile damage behavior of SiC particle reinforced aluminum alloy matrix has been studied using in situ X-ray synchrotron tomography [30]. In situ X-ray synchrotron tomography has been used for 3D observation and quantification of fatigue cracking in Al-Mg-Si alloys [31] and to visualize void volume changes due to thermal fatigue damage in SiC particle reinforced aluminum [32].…”

Determination of Internal Stresses in Lightweight Metal Matrix Composites

“…The gauge volume in the sample is defined by primary and secondary slits. An angle dispersive diffraction measurement on an AlSi7/SiC/70p PRM (Schöbel et al, 2011) is shown in Fig. 5.…”

“…12. In situ neutron stress measurement during thermal cycling of AlSi7/SiC/60p (RT -350°C) showing the stress changes in the -Al and in the particle stresses (Schöbel et al 2011). …”

“…11 b). A combination of in situ angle dispersive neutron diffraction and in situ synchrotron tomography experiments were performed (Schöbel et al, 2011) to explain this behaviour in terms of internal stresses generated during thermal cycling of the ICM. As explained previously, internal stresses can relax at elevated temperatures.…”