M. Kida (Sp), L. Weber, A. Mortensen, Swiss Federal Institute of Technology, Lausanne (Switzerland)
AlN particle reinforced metal matrix composites are produced by gas-pressure assisted infiltration and
characterized for their thermal conductivity (K). The composites are produced with variable phase contrast
between the dispersion (Kd) and the matrix (Km) spanning a range from Kd<Km (matrix: Cu, Al) to Kd>Km
(matrix: Sn, Pb), aiming at investigating the effect of phase contrast on the thermal conductivity of composites.
The particle size (D) of spherical AlN is also varied from about 20 to 95 microns to study the influence of the
interfacial resistance to heat flow that exists in composites made of at least one electrically insulating phase.
Using theoretical models proposed by Hasselmann and Johnson (H&J) and Bruggemann (DEM) for the thermal
conductivity of composites, interfacial conductance values between AlN and matrices in the composites are
deduced from measured plots of the inverse effective particle conductivity, 1/Kd(eff.), versus 1/D. It is found that
the interfacial conductance at the AlN-metal interface increases as the matrix changes in the series
Pb<Sn<Cu<Al. Data are compared with values in the literature and with predictions of two theoretical models for
the interfacial heat conductance by phonon-phonon interaction, namely the Acoustic-Mismatch Model (AMM) and
the Diffuse-Mismatch Model (DMM).