Solidus Surface of the Al–Ti–Pd System in the Al–AlPd–TiPd–Ti Region

Abstract

The ternary Al–Ti–Pd system has been investigated by light microscopy, electron microprobe analysis, X-ray powder diffraction, and differential temperature analysis in the composition range 0–50 at.% Pd (partial system Al–AlPd–TiPd–Ti) at subsolidus temperatures. The corresponding solidus projection is constructed for the first time. At subsolidus temperatures, there are two ternary compounds, τ₁(Al₆₁Ti₂₆Pd₁₃, AuCu₃ type) and τ₃ (Al₄₄Ti₃₅Pd₂₁, MgZn₂ type), and a continuous solid solution between the isostructural (CsCl type) high-temperature AlPd and TiPd phases (β₀-phase), as well as limited solid solutions based on β-Ti and α-Ti and binary TiAl, Ti₂Al₅, TiAl₃, Al₃Pd₂, and ε phases. The above-mentioned phases participate in 11 four-phase invariant equilibria involving liquid. The corresponding invariant reactions occur in the temperature range between 630 and 1205 °C.