Synergetic Effect of Discontinuous Carbon Fibers and Graphite Flakes on Thermo-Mechanical Properties of Aluminum Matrix Composites Fabricated by Solid–Liquid Phase Sintering

Nabil Chamroune (1) , Florence Delange (2) , Nathalie Caillault (2) , Fabrice Morvan (3) , Yongfeng Lu (4) , Akira Kawasaki (5) , Jean-François Silvain (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 38TEC
3 Recherche & Development - Toyal Europe
4 Department of Electrical Engineering
5 Department of Materials Processing Engineering

Aluminum (Al) matrix composite materials reinforced with graphite flakes (GF) and pitch-based carbon fibers (CF) were fabricated by solid–liquid phase sintering with a small amount of Aluminum–Silicon eutectic alloy (Al-12 wt%Si). The amount of Al–Si is optimized for a carbon content of 50 vol% in order to achieve, in the plane of GF reinforcement, a higher thermal conductivity (TC) and a lower coefficient of thermal expansion (CTE) compared to identical composite material fabricated by conventional powder metallurgy route. Al/(GF + CF) composite materials were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray microscopy and X-ray tomography in order to highlight the distribution of the Al–Si liquid phase and the formation of a carbon network in the aluminum matrix. A small amount of CF allows to control the through-plane CTE without affecting significantly the in-plane TC of the Al-C composites. The (GF + CF) mixture and the solid–liquid phase sintering allow to achieve a TC of 410 W/m K (in-plane direction) and a CTE of 2.4 × 10−6/K (trough-plane direction), which is, for example, applicable for lightweight heat sink material.

Mots clés: Metal-matrix composites (MMCs); Discontinuous reinforcement; Powder processing; Thermal properties

Domaines: Matériaux

Nabil Chamroune, Florence Delange, Nathalie Caillault, Fabrice Morvan, Yongfeng Lu, et al.. Synergetic Effect of Discontinuous Carbon Fibers and Graphite Flakes on Thermo-Mechanical Properties of Aluminum Matrix Composites Fabricated by Solid–Liquid Phase Sintering. Metals and Materials International, 2020, 26 (2), pp.155-167. ⟨10.1007/s12540-019-00324-0⟩. ⟨hal-02294346⟩