Phase equilibria of the Al-Si-La system between 0 and 50 at.% La at 600 and 800 °C

Abstract

The 600 and 800 °C isothermal the sections of Al-Si-La ternary system between 0 and 50 at.% La have been established via a combination of electron microprobe analysis and X-ray powder diffraction. A total of three ternary compounds were confirmed in this work and temporally designated τ1, τ2 and τ3. The three ternary compounds (τ1-τ3) were found at 600 °C. The ternary phase τ1 spans 43.3 at.% to 61.5 at.% Al, 5.0 at.% to 21.3 at.% Si, and 33.5 at.% to 35.5 at.% La. One ternary compound, τ1, was identified at 800 °C. The τ1 phase spans 43.6 at.% to 62.6 at.% Al, 4.1 at.% to 22.5 at.% Si, and 33.1 at.% to 35.2 at.% La. The solubility of Al in LaSi2-α2 is 39.9 at.% and 41.3 at.% at 600 and 800 °C, respectively. The solubility of Si in Al2La at both 600 and 800 °C is extremely small.