Phase-Field Simulation of Microstructure Formation in Gas-Atomized Al-Cu-Li-Mg Powders

• Published in: Materials Vol. 16; no. 4; p. 1677
• Main Authors: Phyu, May Pwint, Adjei-Kyeremeh, Frank, Suwanpinij, Piyada, Raffeis, Iris, Apel, Markus, Bührig-Polaczek, Andreas
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 17.02.2023; MDPI
• Subjects: Additive manufacturing; Alloys; Aluminum; Aluminum alloys; Al–Cu; Al–Cu–Li; Al–Cu–Li–Mg; Atomic properties; Atomizing; Cooling; Copper; Fractions; Gas atomization; Heat treatment; Investigations; Lithium; Magnesium; Microstructure; Nucleation; phase field simulation; powder; Powders; Precipitates; Rapid solidification; Simulation; Software; Solid solubility; Solidification; Solids; Technology application; Thermomechanical treatment; Germany; phase field simulation; gas atomization; powder; Al–Cu–Li; Al–Cu; Al–Cu–Li–Mg
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16041677

Al-Cu-Li (2xxx series) powders for additive manufacturing processes are often produced by gas atomization, a rapid solidification process. The microstructural evolution of gas-atomized powder particles during solidification was investigated by phase-field simulations using the software tool MICRESS. The following topics were investigated: (1) the microsegregation of copper and lithium in the particle, and the impact of lithium addition on the formation of secondary phases in Al-2.63Cu and Al-2.63Cu-1.56Li systems, (2) the effect of magnesium on the nucleation and final mass fraction of T (Al CuLi) growing from the melt, and (3) the effect of increased magnesium content on the T and S' (AlCu Mg) phase fractions. It is observed that the addition of lithium into the Al-Cu system leads to a decrease in the solid solubility of copper in the primary matrix; consequently, more copper atoms segregate in the interdendritic regions resulting in a greater mass fraction of secondary precipitates. Our result agrees with findings on the beneficial impact of magnesium on the nucleation and precipitation kinetics of T precipitates in the conventional casting process with further thermomechanical heat treatments. Moreover, it is observed that the increase in magnesium from 0.28 wt.% to 0.35 wt.% does not significantly affect the nucleation and the amount of the T phase, whereas a decrease in T phase fraction and a delay of T formation are encountered when magnesium content is further raised to 0.49 wt.%.