Derivation of the liquidus surface projection for the Al-Pt-Ru system from as-cast samples

Abstract

The liquidus surface projection for the Al-Pt-Ru ternary system has been determined based on the micro-structural characterisation of arc-melted alloys. The liquidus surface is dominated by the similarity to RuAl phase, and slopes down to the Al-rich corner. Two new ternary phases similar to Ru12Pt15Al73 and similar to Ru18Pt28Al64 were observed near the Al-corner. The similarity to Ru12Pt15Al73 phase has a primitive cubic structure, lattice parameter of similar to 0.7721 nm, and is stable to room temperature. The similarity to Ru18Pt28Al64 phase is a high-temperature phase, and decomposes to form similar to Ru12Pt15Al73 and similar to PtAl2. There is a ternary eutectic near 23 at.% Al, 55at.% Pt and 22at.% Ru, whereas most of the other reactions were identified from their microstructures as being peritectic in nature similar to RuAl was found to contain at least 27at.% Pt and the similar to PtAl2 phase exhibited up to 11at.% solubility for ruthenium similar to RuAl6 showed solubility of at least 10at.% platinum. Most of the other phases showed more limited solubilities for the ternary element: similar to RuAl2, similar to Pt2Al3 and similar to PtAl contained only about 2at.% of the third component similar to Ru4Al13 has less than 1at.% solubility for platinum.