TG7: Electron beam weld on a high strength Al alloy

An aluminium alloy (AA6061 T6 – Al-Mg-Si precipitation hardened alloy of the 6xxx series) with an autogenous electron beam weld along the middle of the specimen is being studied by Task Group 7.

 

The 6061 alloy is a high strength aluminium alloy thanks to a specific heat treatment to obtain the largest density of hardening β’’ precipitates (i.e. T6 state). In order to have realistic welding conditions and also get reproducible results, a fusion line was performed on different 6061-T6 plates with different welding velocities. The dimensions of the plates are 200 x 180 x 20 mm3. The thermal cycles above 200°C change drastically the microstructure leading to a modification of the mechanical behaviour of the alloy (softening and natural ageing) and thus having consequences on typical residual stress profiles for such a weld configuration in comparison with steel. The specimen can be used both for material and microstructure model calibration and residual stress measurements.

A circular specimen (thickness is 40 mm at welding stage prior to machining to 20 mm) is also available to check differences between stress profile obtained with straight and circular welds.