Characterization of a high strength Al-alloy interlayer for mechanical bonding of Ti to AZ31 and associated tri-layered clad

The Al 6081 alloy is proposed as a favorable interlayer alloy with satisfactory deformability characteristics; high strength; least reactivity and melting temperature for high temperature joining of pure Ti and AZ 31. Titanium and Magnesium sheets with Al–0.81 Mg–0.9 Si alloy interlayer plate were joined by cold-roll bonding and subsequent annealing treatment. The maximum strength after annealing at 550 °C is due to the combined effect of the precipitation strengthening of Al–Mg–Zn interlayer and static strain aging. The most pronounced increase in the Vickers microhardness (from 49.2 to 74.5 Hv) was observed in the Al 6081 interface with AZ31 and Ti, thus indicating Al 6081 as a sound bonding interlayer with a lower melting temperature, initial excellent deformability and high strength after joining. With the increase in heat-treatment temperature, the tensile strength increased initially up to 550 °C and then decreased with the increase in annealing temperature to levels above 550 °C. The threshold deformation is about 44% of the total rolling reduction in a single rolling pass. The highest mechanical properties were 35 MPa in the composite – which was obtained by 550 °C/2 h annealing treatment.