Synthesis by Vacuum Infiltration, Microstructure, and Thermo‐Physical Properties of Graphite–Aluminum Composite

Abstract

Graphite prefabricated blocks are fabricated using natural flake graphite and pore-forming agent of urea, and then high volume fraction graphite-aluminum (Gr-Al) composites are fabricated applying graphite prefabricated blocks and aluminum alloy (ZL101) by vacuum infiltration process for the electronic packaging materials. The microstructures of graphite prefabricated block and Gr-Al composites are observed in detail, which shows that the graphite maintains a good integrity and arranges uniformly in aluminum alloy. Besides, the result shows the formation of a tightly adhered interface between the side surfaces of the graphite and aluminum alloy matrix, and no detrimental Al 4 C 3 phase is found. Thermal properties of Gr-Al composites are researched perpendicularly to the pressing direction. Thermal conductivity increases from 282 to 398 W mK À1 whereas the volume fraction of flake graphite increases from 40 to 75% in the composites, this reveals that the vacuum infiltration is a very promising method to synthesize Gr-Al composites.

The Effect of Graphite Flake Volume Fraction on the Thermophysical Proper Ties of Graphite Flake/Aluminum Composites

“…This plateau in the TC of the composites is attributed to several factors, including the quantity of GF/Al interfaces, and the quantity of interfaces formed by GF–GF stacking. [ 26 ] At higher graphite flake volume fractions, the number of interfaces and the interfacial thermal resistance impede the effective transfer of heat, resulting in a large deviation of the composite TC from the theoretical value at graphite flake volume fractions above 30%. [ 27 ]…”

“…This plateau in the TC of the composites is attributed to several factors, including the quantity of GF/Al interfaces, and the quantity of interfaces formed by GF-GF stacking. [26] At higher graphite flake volume fractions, the number of interfaces and the interfacial thermal resistance impede the effective transfer of heat, resulting in a large deviation of the composite TC from the theoretical value at graphite flake volume fractions above 30%. [27] As shown in Figure 8b, concerning the through-plane TC of the composites, the graphite flake exhibited low through-plane TC due to its anisotropic nature, with its heat transfer capability predominantly reliant on the aluminum matrix.…”