Experimental and calculated study of the possibility of producing amorphic alloys at the explosive fragmentation of the hot drops in a low-boiling cooler

Аuthors

Ivochkin Y. P., Borodina T. I., Kazakov A. N., Teplyakov I. O.

Joint Institute for High Temperatures of the Russian Academy of Sciences, 13, Izhorskaya str., Moscow, 125412, Russia

Abstract

The presented article describes a relatively simple and technologically advanced method for producing amorphous metals by explosive fragmentation of incandescent liquid metal droplets when they fall into the cooler (cold distilled water). The numerical estimates showed that with a large margin this method can provide the required values of the cooling rate under conditions when the droplet fragments are ~ 1–100 μm in size. The results of the analysis of literature data on steam explosions indicate that the real fragments that form during the fine fragmentation of melts have similar sizes. The experiments to verify the operability of the proposed method for producing amorphous metals were performed in two ways in which metal samples falling in cold water were melted either in a suspended (levitating) state using induction heating, or in a crucible of an electric resistance furnace. The results of studies conducted in the range of changes in the initial temperature of the samples from 300 to 900°C confirmed the possibility of modeling the fragmentation of droplets of fusible metals using the developed technique. The nature of the fragmentation (explosive or quiet) and the degree of fragmentation of the droplets, the shape and size of the fragments are determined mainly by the state (oxidation) of the melt surface and its temperature. The minimum radii of the resulting particles during fine fragmenta- tion did not exceed a few micrometers, and the speed of their expansion during explosive de- struction of the droplet can reach tens of meters per second. The results of an X-ray diffraction study of tin and lead fragments confirm the presence of an amorphous structure of fragments formed during the fine fragmentation of melts during an explosive change in the boiling condi- tions of a cooler.

Keywords:

amorphous metals, steam explosion, fragmentation, cooling rate, boiling, heat exchange.

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