Thermo-derivative analysis of Al-Si-Cu alloy used for surface treatment.

The only effective way to design, produce, analyse and optimise new and existing industrial thermal processes and also laser-based processes is to develop a quantitative knowledge and understanding of the dependence between temperature and time, which allow the desired forming of properties of the final products. The purpose of this paper was the performance of thermo-derivative analysis using the UMSA platform of aluminium alloy cooled at chosen rate, for obtaining characteristics used later for laser treatment and its influence on the microstructure and properties of the surface layer of heat-treated Al-Si-Cu cast aluminium alloys, using the high-power diode laser. The performed laser treatment involves remelting and feeding of ceramic powder into the aluminium surface. The carried out investigations allow to conclude that as a result of alloying of the heat-treated cast aluminium alloys with oxide ceramic powder, a surface layer was obtained with higher hardness compared to non-laser-treated material. The surface layer can be enriched with the powder particle, and in some cases a high-quality top layer is possible to obtain. Also a microstructure refinement of the surface layer was achieved due to the high laser power use and consequently high cooling rate during the crystallisation process. Concerning original practical implications of this work, there was important to investigate the appliance possibility of thermal analysis for further surface treatment for enhancement of the aluminium surface properties, especially the wear resistance and hardness. The scientific reason was also to describe microstructure changes and processes occurred in the laser remelted surface aluminium layer after laser treatment. [ABSTRACT FROM AUTHOR]