STUDIES OF SUPERSATURATED SOLID SOLUTION DECOMPOSITION IN NEW MAGNESIUM RICH ALUMINUM ALLOYS WITH MINOR SCANDIUM ADDITIONS

10.25712/ASTU.1811-1416.2022.04.008

Abstract

The study focuses on decomposition of supersaturated solid solutions in magnesium rich aluminum alloys with small additions of scandium, 1590, 1580 and 01570. The samples produced by casting into a steel mold were used in the study. The samples were analyzed by electrical conductivity comparison method. After as-cast samples examining, they were annealed at various temperatures ranging from 260 ⁰С to 440 ⁰С, with various soaking times ranging from 2 to 100 hours. As-cast state is assumed to be supersaturated solution, decomposing during annealing with decreasing electrical resistance. The subject alloys supersaturated solution 50 % and 80 % decomposition C-curves have been constructed based on this assumption. It has been established that the new 1590 alloy is more thermally stable over the entire range of temperatures under study, while max decomposition rate is observed at 350-370 ⁰С temperature range. 1580 alloy also exhibits significant thermal stability of scandium supersaturated solid solution, at the same time 1570 alloy demonstrates the highest decomposition rate. The most intensive supersaturated solid solution decomposition occurs in 1580 and 1590 alloys at 450-470 ⁰С temperatures.