Laser forming of aluminium and aluminium alloys — microstructural investigation

This paper shows the microstructural development and changes in mechanical properties aluminium and aluminium alloys undergo during the process of laser forming. The resulting structures, grain structure and microstructure were analysed both quantitatively and qualitatively by optical and electron microscopy in order to examine the kind of existing structure zones and their extent. Zones with different substructures can be seen depending on the selected test parameters. The degree of substructural development seems to be a function of all influences and cannot entirely be explained by laser parameters and material characteristics. Obviously, during laser forming several different inhomogeneous particle and dislocation structures develop which are responsible for the strength of the whole composite on the one hand, and for the strength of individual small components of the whole on the other hand. Thus, hardness tests of laser-formed specimens prove the existence of different zones depending on the material and heat treatment.