Processing Ti-Al-Nb Composite Sheet Materials Using Cold Roll Bonding and Reaction Annealing

Abstract

Multi-layered composite sheet materials with nominal composition of Ti-46Al-9Nb (at.%) were successfully processed from Ti, Al and Nb elemental foils using the cold roll bonding technique. To promote the formation of intermetallic compounds in these composites, annealing at 600°C was employed for specimens subjected to various amounts of reduction. The microstructures and phases that formed after cold rolling, the first annealing stage, and the second annealing stage were characterized using scanning electron microscopy (SEM) equipped with an energy dispersive x-ray spectrometer (EDS), transmission electron microscopy (TEM), and x-ray diffraction (XRD). Good bonding was achieved for all rolled samples with a threshold reduction in thickness of about 35% in the first rolling pass. No new phases were formed in the cold rolling stage. Annealing stage did promote the formation of the TiAl3 and NbAl3 phases at the interfaces.