Comparative study of Al – 5Ti – 1B and Al – 3La – 1.5B modifying ligatures

The work was performed at the laboratory on semi-continuous casting unit (SCCU) of the Institute of Non-Ferrous Metals and Materials Science of SFU in order to carry out comparative studies of the modifying ability of Al – 5Ti – 1B ligature and a promising modifying ligature Al –3La – 1.5B. Casting and modification of experimental flat ingots was carried out according to the casting modes, which provide the parameters of the cast workpiece structure as close as possible to the parameters obtained in industrial conditions for ingots with a thickness of at least 300 mm. The paper presents the results of quantitative analysis of the microstructure of Al – 5Ti – 1B and Al – 3La – 1.5B ligatures. The paper shows that when 8079 aluminum alloy is modified with Al – 5Ti – 1B ligature rod at the rate of 0.5–1.5 kg/t metal, the average grain size decreases from 190 to 129 μm and there is a zone of columnar crystals, but at the rate of 2–2.5 kg/t metal, the grain size decreases to 100 and 90 μm, respectively, with the complete absence of columnar crystals zone. The paper shows the results of the experiment on modification with Al – 3La – 1.5B ligature at ligature bar consumption from 0.5–1.5 kg/t metal, where the average size in the obtained ingot samples was from 180 to 100 μm, but at modifier consumption from 2–2.5 kg/t metal the average grain size decreases to 99 and 86 μm, respectively. The paper shows that, according to the results of the experiments, the modifying ligature Al – 3La – 1.5B has better modifying ability in comparison with the ligature Al – 5Ti – 1B regardless of oxide film contamination and higher amount of non-metallic inclusions. The study was funded by the Russian Science Foundation grant No. 24-29-00053, https://rscf.ru/project/24-29-00053/.