Investigation of the Al–Ti–Pt alloy system at 1100 °C

► Al–Ti–Pt alloys were investigated at 1100 °C. ► New five ternary phases were revealed. ► Partial isothermal section of the Al–Ti–Pt diagram at 1100 °C was determined. The 1100 °C isothermal section of the Al–Ti–Pt system was experimentally studied in the compositional region below 50 at.% Pt. Most of the binary Al–Ti and Al–Pt intermetallics dissolve about 1.5–3.5 at.% of the third element. Only TiAl and Ti 3Al contain up to ∼5.5 at.% Pt and Al 2Pt ∼13 at.% Ti. The Ti 3Pt, Ti 3Pt 4 and TiPt phases extend up to 7.5, 9 and 30 at.% Al, respectively. The homogeneity range of the ternary phase τ 1 extends from Al 63.3Ti 30.6Pt 6.1 to Al 69.0Ti 24.2Pt 6.6 and that of τ 2 from Al 44.1Ti 34.0Pt 21.9 to Al 55.1Ti 20.9Pt 24.0. The τ 3-phase is formed in the compositional region from Al 37Ti 37.5Pt 25.5 to Al 42Ti 32Pt 26. Only the Nb(Ir,Al) 2-type structure of the latter was revealed. The τ 4-phase exists between Al 31.3Ti 33.7Pt 35 and Al 36.6Ti 29.4Pt 34 while the τ 5-phase exists between Al 12.9Ti 58.9Pt 28.2 and Al 27.3Ti 57.3Pt 15.4. Apart from these previously reported phases, five new ternary compounds designated τ 6 to τ 10 were revealed. The τ 6-phase exists between the Al 25.5Ti 54.2Pt 20.3 and the Al 30Ti 54Pt 16 compositions, and probably has a primitive cubic structure with a = 0.68477(6) nm. The τ 7-phase was found to be formed around the Al 12Ti 51Pt 37 composition, τ 8, τ 9 and τ 10-phases exist in the compositional ranges of Al 28.5Ti 55Pt 27.5 to Al 33.7Ti 40Pt 26.3, Al 34.5Ti 48Pt 17.5 to Al 38Ti 44Pt 18 and Al 32.6Ti 44.3Pt 23.1 to Al 37.4Ti 41Pt 21.6, respectively.