Tensile bond strength of cold roll bonded aluminium sheets

Sheets of AA1200 and AA3103 aluminium alloys were roll bonded at room temperature and the bond strength across the interface was tested in tension mode. Aluminium rods were glued to the two faces of a coin sample machined from the roll bonded sheet and the whole combination was pulled in tension to open up the bonded interface. The bond strength was calculated from the load required to cause failure at the bonding interface. Studies were carried out on the roll bonding of sheets in the H19 temper and in the O temper. The effects of thickness reduction and annealing treatment on the bond strength were evaluated. As opposed to the conventional shear tests showing a clear threshold deformation, a gradual increase in bond strength with increasing rolling reduction is observed.

► Bond strength in the tensile mode up to 40 MPa has been measured by the new test.
► Tensile bond strengths in different temper conditions have been distinguished.
► A broad range of deformations over which bonding progressively develops is revealed.
► The increase in tensile bond strength with rolling reduction differs with tempers.
► Deformation prior to roll bonding has a positive influence on tensile bond strength.