A comprehensive understanding of melt quality is of paramount importance for the control and prediction of actual casting characteristics. Among many phenomenon that occur during the solidification of castings, there are four that control structure and consequently mechanical properties: chemical composition, liquid metal treatment, cooling rate and temperature gradient. The cooling rate and alloy composition are most important among them. This paper investigates the effect of the major alloying elements (silicon and copper) of AlSi-Cu alloys on the size of secondary dendrite arm spacing. It has been shown that both alloying elements have reasonable influence on the refinement of this solidification parameter
The impact of small addition of zirconium in hypoeutectic commercial AlSi10MgCu alloys on their mechanical properties (hardness) in as cast and thermally treated conditions was investigated. Small addition of zirconium does not change significantly the as cast and heat-treated microstructure of investigated alloys except to reduce the SDAS and grain size of primary α-aluminium phases. Addition of zirconium up to 0.14 wt. percentage increases the hardness of investigated alloys in as cast conditions. The increase in the hardness of samples after various solid solution times can correlate very well with the formation of small needle like coherent Al3Zr particles.
Comprehensive understanding of the melt quality is of vital importance for foundry man. The effect of each particular element need to be properly analysed. Therefore, the aim of this paper was to analyse the impact of various content of zirconium on the solidification path and structural characteristics (SDAS, grain size, porosity) of as cast commercial AlSi10MgCu alloys. It has been found that addition of zirconium up to 0.24 wt.% reduce significantly the grains size (from 3.5 mm to 1.2 mm), SDAS (from 57.3 µm to 50.4 µm) and porosity (from 19% to 5%), leading to production of sound cast parts.