A novel ceramic-metal composite with continuous interconnected ceramic and metal phases has been fabricated from sintered porous particulate AlN preforms infiltrated with magnesium. The 48 vol. % AlN composites are fabricated by pressureless infiltration in argon in the temperature range of 870 °C to 960 °C. An increase in the infiltration rate is observed as the temperature increases. Results on the mechanical characterization of the composites indicate an elastic modulus of 90 to 110 GPa and hardness of 70 to 80 HRB. The tensile strength calculated by the shear punch test method ranges from 260 to 390 MPa. As a general rule, it is observed that the lower the infiltration temperature, the higher the tensile strength. The linear coefficient of thermal expansion of the infiltrated composites in the temperature range of 215 to 315 °C is 7.65 x 10-6 °C-1. This value is lower than those found for similar Al/AlN composites reported in the literature.