a method of making filamentary reinforced metallic structures is disclosed . the method uses a stack of workpieces having two principal opposed surfaces . at least one of the outer workpieces comprises at least one inner sheet made of a metal matrix material reinforced with filamentary material and two cover sheets which sandwich the inner sheets and which extend beyond the periphery of the at least one inner sheet . selected area of the workpieces are treated to prevent bonding at those areas . the workpieces are stacked and positioned between shaping members such that they enclose at least one chamber of at least one of the shaping members . the workpieces are heated to a temperature sufficient to produce diffusion bonding at preselected untreated areas and compressive pressure is applied , both of which are maintained for a sufficient time so as to consolidate the at least one outer workpiece into a single sheet workpiece comprising an interior reinforced portion with a peripheral monolithic portion and to diffusion bond the stack at the untreated areas . alternately the stack can be press diffusion bonded prior to insertion into the forming apparatus . after bonding , tensile stress is induced , preferably by gas pressure , in at least one consolidated workpiece causing at least a portion of the peripheral monolithic portion to expand superplastically against and into intimate contact with at least one of the shaping members .