Solid State Phase Equilibria of an Al⁻Sn⁻Y Ternary System

A complete understanding of the solid-state phase equilibria of the ternary Al⁻Sn⁻Y system is essential for the development of both Al-based structural materials and Sn-based lead-free solders. In this work, the phase relationships in the Al⁻Sn⁻Y ternary system at 473 K were investigated mainly by means of X-ray powder diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) with energy disperse spectroscopy (EDS) analysis. The existence of 12 binary compounds, namely Sn₃Y, Sn₅Y₂, Sn₂Y, Sn Y , Sn₄Y₅, Sn₃Y₅, AlY₂, Al₃Y₅, Al₂Y₃, AlY, Al₂Y and α⁻Al₃Y, was confirmed. Controversial phases (Sn₅Y₂ and Al₃Y₅) were found in this work. This isothermal section consisted of 15 single-phase regions, 27 two-phase regions and 13 three-phase regions. No ternary compounds were found and none of the other phases in this system revealed a remarkable solid solution at 473 K.