Fabrication of metallic intermetallic laminate (MIL) composites

FABRICATION OF METALLIC INTERMETALLIC LAMINATE(MIL) COMPOSITESSinan YILDIZSUMMARYKey Words: Laminate composite, Intermetallic, Diffusion, Fracture toughnessThe goal of this work is to produce a material with high specific strength, toughnessand stiffness for light weight and high performance structural applications. Whilemonolithic titanium is currently being actively used in these applications, highproduction costs limit its widespread use. Ti-Al3Ti laminate system posseses acombination of high strenth, toughness and stiffness at a lower density thanmonolithic titanium or other laminate systems. Further, since aluminum is relativelyinexpensive compared to titanium, the Ti-Al3Ti system is economically moreattractive than monolithic titanium. MIL composites have been produced fromelemental titanium and aluminum foils by a novel one-step process utilizing acontrolled reaction at elevated temperature and pressure. This fabrication process isperformed in open air and produces a fully dense laminate composite. The thicknessof the original titanium and aluminum foils is chosen to ensure that the entirealuminum layer is consumed upon reaction with adjacent titanium layers. Such alayering scheme results in a composite with alternate layers of Al3Ti and residual Tiand the thickness of the final layers are dependent upon the thickness of the originalTi and Al foils.