A study of the Al-Ni-Pt alloy system. Phase equilibria at 1100 and 1300°C

The Al-Ni-Pt phase diagram studied in the whole compositional region at 1300 and 1100 degrees C. The Al2Pt phase found to extend up to at least Al53Ni23Pt24 composition, separating the Al3Pt2 and Al3Ni2 phase fields. The Al-Ni beta phase dissolves up to 38 at.% Pt at 1100 degrees C, while at 1300 degrees C the beta region probably extends between the isostructural CsCl-type phases forming at the Al-Pt and Al-Ni terminals. The AlNi3 phase (gamma') extends up to 35 at.% Pt at practically constant Al concentration, while the high-temperature AlPt3 extends up to 15 at.% Ni. A ternary phase is formed in a wide compositional region between the regions of gamma, gamma', beta, and AlPt3. Apart from the AuCu-type structure of this ternary phase earlier reported, also its C-centered orthorhombic superstructure with a four-times larger unit cell revealed in the high-Al part of the compositional region