Mechanical manipulation of solidification during laser beam welding of aluminum

Mechanical vibrations affect the nucleation and grain growth conditions during solidification and are used as refinement method in the field of casting processes. This paper contributes to identify the influence of applied vibrations during laser beam welding of aluminum on the resulting grain structure. Therefore, it is investigated if the frequency amplitude factor, which suitably describes the grain refinement in casting processes, can be used to describe the grain refinement in laser deep penetration welding. The results show a local grain size reduction and an increase of the percentage of equiaxed grains due to applied excitation. A dependence of the resulting percentage of equiaxed grains on the product of frequency and amplitude cannot be observed within this study.