PRODUCTION TECHNOLOGY FOR Al-ALKALINE EARTH METALS ALLOYING COMPOSITIONS BY MEANS OF CHLORIDE MELT ELECTROLYSIS ON LIQUID ALUMINUM CATHODE

摘要

To improve the structure and mechanical properties of silumin-type alloys, Russian producers are currently using sodium. However, treatment of these alloys with sodium can sometimes lead to remodification of their structure and reduction of fluidity, as well as to fast evaporation and oxidation of sodium.Numerous studies show that, for this purpose, it is possible to replace sodium with other modifiers, such as strontium, barium, and their combinations (1). These modifiers practically never burnout so that the modified alloy retains its structure after multiple resmelting operations and prolonged drooping. Studies of mechanical and technological properties of silumins modified with alkaline earth metals (AEM) showed the optimal concentrations of strontium and barium to be 0.04-0.06 percent and 0.03-0.04 percent, respectively. It also follows from the above data that the best results are obtained by modifying silumin-type alloys with triple alloying compositions having close barium and strontium concentrations. Indeed, an addition of 0.7 percent of such an alloying composition to the alloy AL-9 increases the latter's hardness, strength, and ductility by 9, 27, and 254 percent, respectively.