A method to synthesize metallic glass composites is introduced. In this method, infiltration takes place in the supercooled liquid region where the bulk metallic glass is thermoplastically formed into the second phase. Using this method, the dimensions of the composites are no longer restricted by the critical casting thickness, the second phase can be heterogeneously distributed with the extremes of bulk and surface composites, and the low processing temperature permits the use of a large variety of second phase materials.