Abstract: Preform for carbon-carbon composite part (55) comprising multiple layers of fibrous mats (51, 52, 53) wherein each mat (51, 52, 53) comprises random carbon-containing fibrous matrix (11) having polymeric binder distributed therein and wherein adjacent mats (51, 52, 53) are bound together by additional polymer binder, stitching, and interlocking tabs. Also, method of manufacturing thick multi-layer composite preform, by: providing optionally reconfigurable tool including perforated screen through which vacuum can be drawn; delivering chopped fibers (b) to the tool while drawing vacuum therethrough to form fibrous object; delivering binder (c) to the fibrous object; melting or curing the binder (d) to make a fibrous mat (51, 52, 53); assembling plurality of the fibrous mats (51, 52, 53) and additional binder into the shape of a preform (e); and heat-pressing the resulting mat assembly (f) into finished thick preform (55).

Abstract: Annular brake disc preform (15), wherein 40 to 80 layers of reinforcement fibers of at least two different lengths (11, 19) ranging from 10–60 mm are distributed in a planar gradient throughout the body of the preform, with the reinforcement fibers located near the exterior planes of the disc being predominately shorter fibers (11) and with the reinforcement fibers located in the central planes of the disc being predominately longer fibers (19).