Liquidus Surface and Melting Diagram of the Al–Ti–Pd System in the Al–AlPd–TiPd–Ti Region

Abstract

Crystallization of Al–Ti–Pd alloys is studied by light optical and scanning electron microcopies, x-ray powder diffraction, and differential thermal analysis in the composition range 0–50 at.% Pd in the Al–AlPd–TiPd–Ti partial system. The liquidus surface projection, melting diagram, and Scheil diagram are constructed for the first time. The existence of 11 regions of primary crystallization of ternary compounds, solid solutions based on binary phases, and Ti and Al components is established. The τ₃ phase melts congruently while τ₁ is formed incongruently. Eleven four-phase invariant equilibria involving the liquid phase exist in the system: two of them are congruent and nine incongruent. The invariant four-phase reactions occur in the temperature range between 630 and 1425–1456 °С.