An investigation of the Al–Ni–Rh phase diagram between 50 and 100at% Al

Abstract

The Al-rich part of AleNieRh was studied between 800 and 1080 C. The Al 9 Rh 2 phase was found to contain up to 8 at% Ni. The orthorhombic AleRh 3 6 -phase extends up to 17.5 at% Ni, high-temperature cubic C-Al 5 Rh 2 up to about 10 at% Ni while low-temperature hexagonal H-Al 5 Rh 2 extends up to 4 at% Ni. The Al 7 Rh 3 phases contained up to 3 at% Ni. The solubility of Rh in Al 3 Ni is up to 3 at% and in Al 3 Ni 2 up to 5 at%. The isostructural binary AlNi and AlRh phases probably form a continuous b-range of the CsCl-type solid solutions. A ternary hexagonal phase similar to Al 28 Ir 9 (a ¼ 1.213 and c ¼ 2.626 nm) was found to be formed between Al 76 Ni 4 Rh 20 and Al 76 Ni 13 Rh 11 . The formation of the high-temperature stable decagonal phase was confirmed. Another ternary phase, whose structure is not yet clarified, was revealed around Al 70 Ni 11 Rh 19 . Partial 1080, 1000, 900 and 800 C isothermal sections of the AleNieRh phase diagram are presented.

A contribution to the Al–Ir phase diagram

“…[2] was concluded from its disappearance after annealing, which could be due to the composition of the sample outside its coexistence range. Structures similar to that of Al 28 Ir 9 were already observed in the ternary Al-Ni-Ru [15], Al-Ni-Rh [16] and Al-Pd-Re [17] alloy systems. A hexagonal structure with a ¼ 0.31 and c ¼ 0.52 nm reported in Ref.…”

An investigation of the Al–Pd–Ir phase diagram between 50 and 100 at.% Al

“…The present work continues the study of the binary and ternary alloy phase diagrams of aluminum with platinum metals (see [1][2][3][4][5][6][7][8][9][10][11][12] and references therein). Interest in these alloy systems is due to the formation of complex periodic and quasiperiodic intermetallics attractive for both basic and applied research.…”

Rhodium and Hafnium Influence on the Microstructure, Phase Composition, and Oxidation Resistance of Aluminide Coatings

“…The radius of nickel and rhodium atoms is 135 pm, so rhodium atoms replace nickel atoms in the lattice of the β-NiAl phase and the (Ni,Rh)Al phase is formed. The β-NiAl (atom %: 52.5Al-42.8Ni-4.7Rh) phase was identified in the Ni-Al-Rh alloy after 67 h annealing at 1080 • C [25].…”