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Abstract. In this study, a pneumatic high-temperature droplet generator was used to generate individual droplets (diameter range: 350 -1200 µm) which were cooled under combined cooling conditions. The individual droplets were cooled in a nitrogen atmosphere after ejection and during subsequent free fall. After a defined falling distance, the particles were quenched in either oil or water to further increase their cooling rate. Two alloys in different temperature ranges were used to study the effect of different cooling conditions quantitatively by the analysis of different microstructural features. To show the working range of the droplet generator, a metallic glass FeCo35.1Nb7.7B4.3Si2.8 (liquidus: 1210 °C) was used as a high-temperature alloy, and its resulting amorphous fraction was quantified as an indicator for different cooling conditions. Furthermore, the aluminium alloy AlCu4.5 (liquidus: 650 °C) was solidified under different conditions and the subsequent secondary dendrite arm spacing (SDAS) measurements were analyzed.

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