Development of the laser stir welding process for aluminum laser beam welding

Laser stir welding involves the manipulation of the laser beam to provide hydrodynamic stirring and subsequent healing of the keyhole. Since aluminum alloys tend to be especially sensitive to keyhole stability, the process has been conceived for laser beam welding of these alloys. Based on this potential, evaluations were conducted on 3 mm thick aluminum alloy 6013-T4 using laser beam and laser stir welding processes for producing butt, lap, and fillet welds. Results of the evaluation indicated that the welds produced using the laser stir welding process displayed less weld defects when compared to the laser beam welding process. However, analyses indicated that there were other advantages that could be attributed to the laser stir welding process. These were: the ability of the process to accommodate larger gaps, the production of wider welds at the faying surface for lap welds, and decreasing the sensitivity of wire placement when adding filler wire. This presentation will describe the laser stir welding process and resultant weld characteristics in comparison to laser beam welding. These attributes have been defined based on the results of metallographic analyses, radiographic inspection, and mechanical testing.