2025/12/05 by Astafurova, Elena G., Astapov, Denis O., Zagibalova, Elena A. +3
Engineering · #Additive Manufacturing Materials and Processes #Alloy #Brittleness #FOS: Physical sciences #High Entropy Alloys Studies #Intermetallic #Intermetallics and Advanced Alloy Properties #Microstructure #Nickel aluminide #Phase (matter) #Physical sciences #Titanium aluminide #Ultimate tensile strength
paper · doi:10.48612/letters/2025-4-416-422
openalex publication_date 2025/12/05 · openalex created_date 2025/12/06 · openalex updated_date 2026/07/01
In this paper, we provide electron microscopic and in-situ X-ray study of microstructure in an Ni-Al-Cr intermetallic alloy that has been obtained by a dual-wire electron beam additive manufacturing using commercial NiCr and Al wires. As-built material possesses a dendritic microstructure that is heterogeneous in both elemental and phase compositions. Different intermetallic phases have been identified with high accuracy using transmission electron microscopy: ordered NiAl-based aluminide with particles of disordered Ni3Al-based phase in dendritic areas, and mixture of Ni and ordered Ni3Al phase in interdendrites (all alloyed with Cr). A part of the NiAl-based phase underwent the martensitic transformation B2(NiAl)→L10 during the additive manufacturing process and post-built cooling. According to in-situ XRD analysis under heating of the alloy up to 1273 K, this transformation has a thermoelastic nature, and the L10→B2(NiAl) reverse transformation finish temperature is about 873 K. We have noticed the correlation between the phase composition and the tensile fracture micromechanism of the alloy at room temperature: brittle intermetallic B2‑NiAl, L10‑NiAl and Ni3Al-based phases are responsible for high strength but low elongation of the alloy (the tensile strength is 780 MPa and the elongation is 0.2 %). An intermetallic alloy is designed to produce intermetallic coatings or to repair bulk intermetallic details using the electron beam additive manufacturing.