TAƃSKI Tomasz Silesian University of Technology

Surface Treatment Influence on Properties of the Heat Treated Light Cast Alloys

The goal of this paper is to present the results of the investigations concerning heat and surface treatment of Mg-Al-Zn magnesium alloys. Magnesium are more and more frequently applied wherever the reduction of subassembly mass is significant, desired and feasible. To improve their usable properties, laser treatment has been used, particularly laser remelting and feeding of hard ceramic particles as well as technologies of chemical and physical vapour deposition from CVD and PVD gas phase. The surface treatment of the magnesium alloys was carried out with the use of chemical and physical deposition methods from PA CVD and CAE PVD gas phase and laser surface treatment, including in particular laser feeding of hard ceramic particles into the surface of materials produced, enabling the production of a quasi-composite MMCs (Metal Matrix Composites) structure.. The results of mechanical and functional properties measurements of heat treated samples confirms, that the performed heat treatment, consisting of solution heat treatment with cooling in water, as well aging with cooling in air, causes strengthening of the investigated cast magnesium alloys according to the precipitation strengthening mechanism, induced by inhibition of dislocation movement due to the influence of strain fields of the homogeny distributed precipitates. The combination of properly chosen heat treatment with the possibilities of structure- and phase composition modelling of the magnesium matrix using laser feeding provides an additive increase of mechanical and functional properties by significant grain refinement and production of micro-composite layers with homogeny distributed dispersion phases particle and characteristic zone structure.

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