Phase Formation in Liquid Aluminum Alloys Using LIBS

This technical report evaluates the phase formation of Al3Ti and Al3Zr in liquid aluminum alloys through laser-induced breakdown spectroscopy (LIBS). The study focuses on the Al-rich liquidus lines of Al–Ti and Al–Zr phase diagrams, examining the effects of cooling rates on the concentration of dissolved elements in dilute molten alloys. The experiments reveal that at a cooling rate of 1 °C/min, concentration measurements align with predicted liquidus lines, although discrepancies with existing thermodynamic databases are noted. Faster cooling rates demonstrate nucleation undercooling, which is influenced by both the cooling rate and the initial alloy composition. The findings indicate that the Al3Ti-D022 phase nucleates at lower undercooling compared to the Al3Zr-D023 phase for similar mass compositions. The report emphasizes the importance of accurate phase diagrams in aluminum recycling processes and the role of LIBS in real-time analysis of melt chemistry, contributing to the development of thermodynamic databases for alloy design.