Microstructure and Kinetics of Intermetallic Phase Formation during Solid State Diffusion Bonding in Bimetal Ti/Al

Abstract

In this study, tri-layered Ti/Al composites were synthesized using hot press/roll bonding, and then the annealing treatment was executed in the temperature range of 550–650°C for 2, 4, and 6 h. Interfacial layers were characterized using scanning electron microscopes (SEM), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD). The results of microstructural characterization for all annealing temperatures and times indicated that the Al₃Ti compound is the only intermetallic compound observed in the diffusion layers. The Al₃Ti growth obeyed linear kinetics and was characterized by an activation energy of 128.7 kJ mol^–1. The results indicated that the dominant diffusing component was aluminum and the growth of the Al₃Ti layer occurred mainly at Ti/Al₃Ti interfaces.