Microsoft PowerPoint - poster_Dimitris [tryb zgodności]

The present study continues the research efforts of recent years on the 1 Faculty of Foundry Engineering, AGH University of Science and Technology, 23 Reymonta Street, 30-059, Kraków, Poland 2 School of Materials, The University of Manchester, Grosvenor Street, Manchester, M1 7HS, UK 3 Polish Academy of Sciences, 25 Reymonta Street, 30-059, Kraków, Poland Crystallisation curves Regarding the crystallisation peaks again the unmodified alloy exhibited grain-refinement of the sand-cast Al-20wt%Zn alloy. The aim of the current experimental work is to optimise the grain-refining Ti-addition by achieving a balance of all the desired properties for an as-cast alloy; small grain size, high tensile strength, high damping properties and low porosity are targeted. This paper is focused on the effects of the addition of four master alloys (MAs) containing different amounts of Ti, on the melting and crystallisation behaviour of the Al-Zn20 alloy. Differential Scanning Calorimetry (DSC) was employed in order to compare the base alloy with its four modified variants. These preliminary measurements include the enthalpy/peak area , a smaller peak compared to alloys with MA additions (Fig. 3a). The peak temperature is shifted towards slightly lower temperatures compared to the unmodified base alloy Al-Zn20 (Fig. 3b). The initiation temperature of crystallisation in this case is fairly similar in all alloys, while the end temperature is lower for the initial alloy by approximately 4-5oC. A “shoulder” is obvious on the low temperature side of the peaks, which corresponds to some other phenomenon taking place during crystallisation. The crystallisation temperature range depends quite strongly on the sample dimensions, due to effects from the free surfaces on the nucleation of solidification. On the contrary, the temperature range of the phase transformations and the corresponding temperature ranges. of melting was not affected by this parameter. 0 50 100 150 200 250 H ea t f lo w (m W ) ZnTi4 AlTi5B1 AlTi3C0.15 (Al,Zn)3Ti