Enlightening from γ, γ′ and β phase transformations in Al-Co-Ni alloy system: A review

Structure Evolution of Ni36Al27Co37 Alloy in the Process of Mechanical Alloying and Plasma Spheroidization

“…In the optical micrograph of an etched powder section, -phase is represented by light areas, and -phase is represented by the dark ones [8,26]. It is also confirmed by element distribution maps (Figure 7), where regions enriched with Co correspond to -phase and regions enriched with Al correspond to -phase [7,27]. The latter possesses a B2 structure, and there are no diffraction peaks from the L10 structure; thus, the temperature of the direct martensitic transformation start is below room temperature in the resulting powder.…”

“…In this system, shape memory effect (SME) is observed when the transformation B2 to L1 0 takes place [7]. In these alloys, B2 structure corresponds to the NiAl-type BCC-structure known as β-phase.…”

“…The pure intermetallic compound is nonmagnetic and very brittle, though it also indicates SME. The addition of Co to Ni-Al alloys makes them ferromagnetic and more ductile due to the occurrence of γ-phase with FCC-structure [7,8]. The optimal composition to achieve appropriate functional and mechanical properties lies in a nearequiatomic ratio.…”

Invited viewpoint: in situ nanostructured lamellar composites

“…This would allow for the production of hospital furniture that would be more effective at killing bacteria than stainless steel and for water supply pipes with a high surface area of the inner pipe surface that would assist in controlling Legionella through copper-silver ionization. Other potential uses as a catalyst remain to be established, but L1 2 -Ni 3 Al (c 0 ) is known to be an efficient catalyst toward the methanol decomposition reaction and methane steam reforming processing for hydrogen production [27]. As a result, the Ni-Al-X system could be used to produce pipes with a high surface area of c 0 through selective etching on the inside of…”