INFLUENCE OF HPDL LASER ALLOYING PARAMETERS ON STRUCTURE OF HEAT TREATED LIGHT ALLOYS

There are presented in this paper the investigation results of microstructure as well hardness investigation of the surface layer of cast magnesium alloys after heat treatment alloyed and/ or remelted with ceramic powders using High Power Diode Laser (HPDL). The purpose of this work was to determine the proper laser treatment conditions for surface hardening of the investigation alloys. For investigation of the obtained structure there was used light as well scanning and transmission electron microscopy. By mind of transmission electron microscopy, using bright and dark field technology, as well selected area diffraction method, was it possible to determine the phases occurred in the alloy after laser treatment. The morphology and size of the primary Al alloy phases as well the alloyed ceramic particles was also possible to determine as well the lattice parameters for the present phases. After the laser surface treatment carried out on the heat treated magnesium cast alloys there are visible structural changes concerning the microstructure as well as distribution and morphology of the fed particles occurred in the sample surface, influencing the hardness of the achieved layer. Concerning the laser treatment conditions for surface hardening also the laser power and ceramic powder feed rate was studied. The structure of the surface laser tray changes in a way, that there are zones detected like the remelting zone the heat influence zone. This investigation with appliance of HPDL laser for Al alloys makes it possible to obtain or develop, interesting technology very attractive for different industry branches.