Anisotropy in thermal conductivity of graphite flakes–SiCp/matrix composites: Implications in heat sinking design for thermal management applications

Abstract

Within the frame of heat dissipation for electronics, a very interesting family of anisotropic composite materials, fabricated by liquid infiltration of a matrix into preforms of oriented graphite flakes and SiC particles, has been recently proposed. Aiming to investigate the implications of the inherent anisotropy of these composites on their thermal conductivity, and hence on their potential applications, materials with matrices of Al-12wt.%Si alloy and epoxy polymer have been fabricated. Samples have been cut at a variable angle with respect to the flakes plane and thermal conductivity has been measured by means of two standard techniques, namely, steady state technique and laser flash method. Experimental results are presented and discussed in terms of current models, from which important technological implications for heat sinking design can be derived.

Effect of flake powder metallurgy on thermal conductivity of graphite flakes reinforced aluminum matrix composites

“…The hot pressing temperature was monitored via a K-type thermocouple located 2 mm from the sample in the steel mold. Considering that the GF, like carbon fibers [8,26,30], tends to be aligned perpendicularly to the uniaxial compressive stress, the cylindrical Al/GF composites were machined to Ø6 × 3.5 mm 3 in order to measure thermal conductivity in the in-plane and transverse direction ( Fig. 5).…”

“…Al-graphene composites with bioinspired nanolaminated structure were fabricated with higher strengthening [23]. In functional metal-matrix composite (MMC), extended works have been reported on reactivity between matrix and reinforcement [24,25], dispersion and orientation of reinforcement [26], fabrication process [4] (sintering, squeeze casting [27,28], pressure infiltration process [29]), sintering process (solid-state [8,10] and liquid-phase sintering [30]). Figure 1 shows the in-plane TC (along the plane of graphite flake) of various Al/GF composite materials reported in the literature.…”

Synergistic effects of fibre arrangements on the microstructure and properties of organic composite materials

“…When these latter are oriented in the parallel direction of the heat transfer, diffusivity is higher. 16 This is the case for the two investigated materials, diffusivity is higher in the transversal direction where carbonaceous particles are more elongated in this direction and thus more interconnected (Figure 14). This arrangement of conductive particles creates shorter path of heat transfer in the transversal direction.…”

“…It should be considered that thermal conductivity depends highly on the anisotropy of the material. 16 In fact, this property is affected by the distribution and orientation of conductive particles in the material. Diffusivity is higher in transverse direction for the two materials.…”

Study on Fabrication and Properties of Graphite/Al Composites by Hot Isostatic Pressing-Rolling Process

“…It is well known that poor wettability and interfacial reaction which produces Al 4 C 3 between aluminum and graphite were harmful for the thermal stability, mechanical properties, and stacking of graphite leaves almost no space between the flakes, which make liquid metal difficult to infiltration in [ 14 ]. Besides, to take advantage of the anisotropic thermal properties of graphite, it is very important to control the orientation of graphite [ 15 ].…”