Investigations on laser beam brazing of aluminium alloys in butt joint configuration within an oxygen-free atmosphere
Materials Science and Engineering (MSE)
Laser beam brazing is an established manufacturing process, which is preferably used in the automotive industry for the shell area of the car body, due to its low heat input and the aesthetically appealing joints. However, brazing of materials with a high oxygen affinity, such as aluminium, requires the removal of the surface oxides prior to the brazing process, commonly through the application of chemical fluxes that may be harmful to environment and health. In the presented study, an oxygen-free atmosphere was created by adding monosilane to the process gas, which results in an oxygen partial pressure that is adequate to an extremely high vacuum. The atmosphere inhibits renewed oxidation of the material surface after it has been deoxidised by pulsed laser radiation with a wavelength of 1064 nm, pulse length of 45 ns and a pulse energy of 180 μJ. This way joints in butt joint configuration are brazed which are evaluated by means of metallographic cross-sectio ns and mechanical testing. The results are compared with conventional joints using flux.