Cast alloys on the Zn matrix and of an increased Al content are characterised by good technological and mechanical properties, due to which they should meet special, more demanding requirements. However, the basic problem in these alloys technology, apart from a high tendency for gases pick-up and oxidation of liquid metals, is a tendency to form coarse-grained dendritic structures in castings solidifying in sand moulds, what - in turn - unfavourably influences their plastic properties [1, 2, 7, 11]. Therefore several treatments aimed at obtaining fine-grained structure and improving plastic properties are applied in these alloys technology. The presented study concerns the modification process of binary, middle-aluminium Zn alloys performed by additions of inoculants containing titanium and investigations of these modifications influence on the structure refinement degree. The Zn-10wt% Al (ZnAl10) alloy modified, before pouring into a sand mould, either by addition of the traditional inoculant i.e. Al-3wt% Ti-0.15wt% C (AlTi3C0.15 – TiCAl) or the new inoculant Zn-3.2wt% Ti (ZnTi3.2) was tested. Within investigations the thermal analysis was performed, especially cooling curves and their first derivatives, and also measurements by means of the differential scanning calorimetry (DSC), with a purpose of determining the modification influence on undercooling degree changes. Microstructures of the tested alloy were observed by the light microscopy (LM). The applied modification of middle-aluminium zinc alloys by AlTi3C0.15 and ZnTi3.2 inoculants causes a significant refinement of the alloy structure. Inoculants applied in investigations have a strong nucleating activity, which is confirmed by decreasing of undercooling and the temperature recalescence in cooling curves, which occurs simultaneously with grain refinements.
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