Eutectic isolation in Mg-Al-Cu-Li(-Y) alloys by centrifugal processing

Mg₅₆Al₃₀Li₇Cu₇ and Mg₅₀Al₃₀Y₆Li₇Cu₇ melts were processed for 2 h in a centrifuge at an inertial acceleration of 60 000g and a temperature of 530°C. Subsequent slow cooling across the melting temperature during continuous centrifugation leads to a pronounced stratification, with primary phases forming at the sample ends and binary and ternary eutectic microstructures forming in the middle of the sample, as resolved by scanning electron microscopy. In both cases, the ternary eutectic has the approximate nominal composition Mg₅₈Al₃₃Li₆Cu_2.5(Y_0.5). The implications of the use of high-temperature centrifugation as a new tool for finding deep eutectic compositions, which have the potential to form bulk metallic glasses, are discussed.