Composite bodies made by a silicon metal infiltration process that feature a metal phase in addition to any residual silicon phase. Not only does this give the composite material engineer greater flexibility in designing or tailoring the physical properties of the resulting composite material, but the infiltrant also can be engineered compositionally to have much diminished amounts of expansion upon solidification, thereby enhancing net-shape-making capabilities. These and other consequences of engineering the metal component of composite bodies made by silicon infiltration permit the fabrication of large structures of complex shape. Certain liquid-based preforming techniques are particularly well suited to the task, particularly where a high volumetric loading of the reinforcement component is desired.