The use of micro-mechanical material laws to describe the deformation and failure behaviour of aluminium weld joints. Part I

The behaviour of a MIG-welded AlMgSil-T6/AlSi5 joint with precipitation hardened base metal was investigated and evaluated by fracture mechanics and micro-mechanical methods. For this, damage development in tensile specimens was quantitatively analysed by metallographic and fractographic investigations. The experimentally determined damage distribution agrees well with the numerical results obtained from the Gurson model. The use of damage parameters determined from the tensile tests does not yet lead to satisfactory prediction of the fracture behaviour of fracture mechanics M(T) specimens with cracks in various zones. Consideration of pore shape development or improved pore formation criteria in aluminium materials may contribute to better transferability of the concept. As a pragmatic solution it is proposed to determine the damage parameters for the modelling of structures with cracks directly from fracture mechanics specimens, or to verify them in this way.