<title>Surface melting of AlSi10Mg with CO2 laser radiation</title>

The melting of sandcast and chillcast A1Si1OMg alloys with CO laser radiation is investigated as a function of processing variables to improve tñe surface properties with respect to wear resistance by self-quenching and rapid solidification. To overcome the high reflectivity of aluminium alloys graphite coatings were used to increase the energy coupling. In order to avoid any chemical reactions with the amblent, shielding gases such as C02, He, Ar and N2 have been used. The results of microstructural refinement are discussed in view of processing variables, melt dynamics, improvement in wear and efficiency of energy coupling in combination with calculations of the processing geometry via diffusive and convective heat transfer.