Simulating the dependence of the filler wire feeding on the wire size in the hybrid metal extrusion & bonding (HYB) process

HYB is a new solid-state joining method for metals and alloys that utilizes continuous extrusion as a technique to enable aluminium filler metal (FM) additions. In the present work, a finite element (FE) model for the filler wire feeding inside the HYB PinPoint extruder has been developed and implemented within the commercial software package DEFORM 3DTM. Adaptive remeshing is used to handle the high mesh distortions occurring during simulation. Moreover, modelling of the FM flow stress as a function of strain, strain rate and temperature is done by employing a modified version of the Johnson-Cook constitutive equation and experimental tensile test data for the AA6082 filler wire. In the numerical simulations, the feeding behaviour of filler wires with diameters of 1.2, 1.4 and 1.6 mm, respectively has been explored. The results show that the filler wire feeding is sensitive to variations in the extrusion chamber geometry. For the specific combinations of wire diameters and extrusion chamber geometries examined, the φ1.4 mm wire appears to be the best choice when it comes to reducing feeding problems related to buckling & breaking of the filler wire during extrusion & joining.