Investigating the Al-Cr-La ternary system: Al-rich corner phase equilibria at 600°C

The phase equilibria of the ternary phase system Al-Cr-La were investigated in the Al-rich corner at 600°C, with minimum Al content of 98.77 at.%. The formed phases, transformation temperatures (specifically liquidus and solidus) and microstructure evolution were experimentally determined by isothermal annealing at 600°C for 600 hours and Differential Scanning Calorimetry (DSC) analysis. Scanning Electron Microscope (SEM) equipped with Energy-Dispersive X-ray Spectroscopy (EDXS) was employed to completely characterize the samples. The equilibrium microstructure state consists of the (Al), the binary phase {Al₄₅} <![CDATA[ Cr_7 and the ternary phase LaCr_2 > {Al₂₀} in the samples with increased Cr content (from 0.03 up to 1.12 at.%), while it consists of the (Al), the mixture (Al) + {Al₁₁} <![CDATA[ La_3 and the ternary LaCr_2 > {Al₂₀} phase in the samples with increased La content (from 0.03 up to 0.45 at.%). It was observed that even the small amount of alloying elements leads to the formation of ternary phase.