Atomic diffusion mechanism and interface nanomechanics in the Al/Ti composite structures

Abstract In this work, Al/Ti composite structures are obtained by isothermal compression at 550 °C and then annealed at 500–650 °C, respectively. The microstructure, elemental diffusion behavior, bonding characteristic and nanomechanics at the Al/Ti interface are systematically investigated by different material characterization methods. A nanoscale Al–Ti solid solution is formed at the contact interface between AA6063 and Ti–6Al–4V sheet, and TiAl3 is generated after annealing. Si-enriched clusters at the Ti/TiAl3 interface and Mg-enriched clusters at the Al/TiAl3 interface are observed, which retards the growth of the TiAl3 layer. With an increase in the annealing temperature, the average thickness of the TiAl3 layer dramatically increases and the enrichment of Si and Mg decreases. Ordered TiAl3 is gradually formed through the atomic rearrangement in the Ti–Al–Si–V structures at the three-dimensional Ti/TiAl3 interface, accompanied by the transformation of an order–disorder–order structure. The nanomechanics at the interface is closely related to the annealing temperature, elemental diffusion and microstructure characteristic, which is also discussed.