Influence of Laser Feeding on Structure and Properties of Cast Aluminium Alloy Surface

The modern methods for surface layer engineering in current surface laser treatments, is LSA treatment, where there are small amounts of alloying additions introduced into the surface layer of the matrix material in the form of ceramic particle powders with different properties influencing the surface layer application possibilities. It was possible to produce a layer consisting of the heat affected zone, transition zone and remelted zone, without cracks and defects as well as with a slightly higher hardness value compared to the non remelted material. The laser power range was chosen to be 1.5–2.0 kW and implicated by a process speed rate in the range of 0.25–0.75 m/min. The purpose of this work is to apply High Power Diode Laser (HPDL) for the improvement of aluminum’s mechanical properties, especially the surface hardness. This study was conducted to determine the effect of SiC powder addition on the structure and the mechanical properties as well as the structural changes occurring during the rapid solidification process. The main findings were, that the obtained surface layer is without cracks and defects as well as having a comparably higher hardness value when compared to the non-remelted material. The hardness value increases according to the laser power used so that the highest power applied gives the highest hardness value in the remelted layer.Also, the distribution of the SiC particles is good, but the particles are mainly present in the upper part of the surface layer. The hardness value increases in general according to the laser power used so that the highest power applied renders the highest hardness value in the remelted layer. The main goal of this work is to investigate and determine the effect of HPDL remelting and alloying on the cast Al-Si-Cu cast aluminium alloy structure to recognise the possibility for application in real working conditions mainly for light metal constructions as in the many branches of the industry.