Assessment of the Mechanical Integrity of a 2 mm AA6060-T6 Butt Weld Produced Using the Hybrid Metal Extrusion & Bonding (HYB) Process – Part I: Bend Test Results

Abstract

The present investigation is concerned with butt welding of 2 mm thin AA6060-T6 profiles at room temperature (RT), using the HYB process and AA6082-T4 as filler material. In the as-welded condition, the 1000 mm long butt weld is seen to be straight and free from global distortions. At the same time both weld faces appear slick and display a nice surface finish. However, cold flow results in the formation of internal voids in the beginning of the weld, but these defects gradually disappear as the temperature distribution approaches pseudo-steady state further ahead. Still, root cracks evolved during instrumented three-point bend testing along the entire length of the weld because of “kissing” bond formation. Based on ABAQUS simulations of the bend test it is concluded that they form when the plastic tensile strain component on the root side of the weld exceeds about 0.38. Hence, the “kissing” bond formation is not devastating for the resulting mechanical integrity of the joint.