Thermal-strain-induced dynamic recrystallization and elements partitioning at heterogeneous bonding interfaces of titanium alloys

Abstract

• Fine recrystallization grains are formed at the heterogeneous bonding interface. • The original bonding interfaces transform into different curved grain boundaries. • Elements partitioning occurs across the bonding interface with Mo and Nb diffusion. • No harmful heterogeneous precipitates formed around the bonding interface. The laminated bonding interfaces of Ti6Al3Nb2Zr1Mo (Ti-6321) and Ti6Al4V (TC4) form an interfacial transition zone during plastic deformation bonding. The interfacial dynamic recrystallization by lattice and subgrain rotation occurs around the bonding interface, inducing the formation of fine grains at the interface. The original bonding interface transforms into curved low or high-angle grain boundaries, suggesting that the bonding interface of dissimilar titanium alloys achieves complete metallurgical bonding. Moreover, elements partitioning occurs across the bonding interface with Mo and Nb in the α phase of Ti-6321 diffusing into the β phase of the TC4 side adjacent to the bonding interface.