Diamond/metal composites with diamond contents between 57 and 72 vol% have been produced by gas pressure assisted liquid metal infiltration using Ag-3 wt% Si and Al-2 wt% Cu as matrix. The experimental data cover a range of Young's moduli from 300 to 425 GPa and 245 to 370 GPa for the Ag-3Si and the Al-2Cu-based composites, respectively. Experimental Young's moduli are compared to the Mori-Tanaka mean field scheme (MTM), the generalized self-consistent scheme (GSCS), the bimodal hard sphere model (TBHS), and the differential effective medium scheme (DEM). At the lower end of volume fractions investigated, the predictions by the GSCS, the TBHS, and the DEM are very close to each other and to the experimental results while the MTM is clearly lower. With increasing volume fraction the differences between the models accentuate and the data up to 72 vol% of diamond are best described by the DEM. (C) 2009 Elsevier Ltd. All rights reserved.