Processing Ti-Al-Nb multi-layered composites from elemetal foils using accumulative roll bonding

Intermetallic compounds and alloys in the form of sheet materials are ideal candidates for the manufacturing of supersonic spacecrafts. One particular intermetallie that has been receiving considerable attention for this application is the alloy Ti-46AI-9Nb (at%). In this study, accumulative roll bonding (ARB) is used to process multi-layered composites with a nominal composition of Ti-46AI-9Nb (at%) from elemental foils. The microstructures of the multilayered composites that were subjected to different levels of rolling reduction were characterized by scanning electron microscopy (SEM). The hard Ti and Nb layers were observed to neck and break down due to the repeated mechanical deformation, and the Ti and Nb particles embedded in the soft AI matrix. X-ray diffraction (XRD) patterns showed only reflection of the elements, which indicates that no detectable solid-state reactions occurred. Differential thermal analysis (DTA) was also used to characterize the effect of rolling strain on the solid-state reaction and phase formation in the composites during annealing. Tensile testing and fractography of the tensile test specimens were utilized to evaluate the mechanical properties of the processed multi-layered sheet materials.