By applying the laser dispersing technology. TiC-particles are added to surface layers of aluminium alloys in order to improve the wear resistance. The blown powder process is investigated theoretically by a mathematical model. Experiments were carried out with a line-shaped CO_2-laser beam and a tilted nozzle. As discovered by theoretical analysis, during travelling through the beam melting of the powder can take place under extreme conditions of high beam intensity and small powder particle size, while usually the powder is only preheated by the laser beam. When entering the melt pool, the powder achieves thermal equilibrium with the pool within a few microseconds. Experiments where optimised for enabling a homogeneous powder distribution for single as well as for overlapping processed tracks. The distribution is affected by the injection momentum of the powder into the pool, by the melt pool geometry and by the Marangoni effect. The investigations reveal that optimisation of the beam shape, of the nozzle arrangement and of the grain size are desirable.
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