Finite Element analysis of dissimilar aluminium weldings based on X-ray computed tomography and instrumented indentation data.Wednesday (27.05.2020) 10:20 - 10:40
In welded structures made from Aluminium wrought and high pressure die casting alloys, different defects related to welding can occur. Aluminium wrought alloys tend to exhibit heat cracking phenomena as well as a degradation of the heat affected zone (HAZ), whereas Aluminium cast alloys predominantly show weld porosity and incomplete fusion defects. When welding Aluminium wrought alloys to Aluminium cast alloys, the risk of heat cracking is significantly reduced due to the Silicon and Magnesium content of the cast alloy. However, the occurrence of various irregularities, such as porosity, incomplete fusion, surface irregularities and the degradation of the HAZ depends on the welding process, the process parameters, the composition the aluminium alloy as well as on the casting process.
Aiming to describe the behaviour of these geometrical defects and the metallurgical condition of dissimilar Aluminium weldings under static loading, the following approach is undertaken within the current study: Firstly, tensile test specimen and metallurgic cross sections are taken from various weldments. Secondly, the tensile testing probes are investigated by the use of X-ray computed tomography (XCT) and the cross sections by instrumented indentation testing (IIT). In a next step, XCT voxel data is converted into a tetrahedral FE mesh containing regions of differing material laws based on the outcome of the IIT. Afterwards, a numerical FE simulation of the tensile test is carried out using the created meshes of the test specimens, which include all detected irregularities. Subsequently, a tensile test is performed on the physical test probe and the results of simulation and experiment are compared. Based on the results the behaviour of the different welding defects under static loading is discussed.