The Peculiarities of the Structure of the Ni–40Cr–3.5Al Alloy during Nitriding

• Published in: Physics of metals and metallography 2022-08, Vol.123 (8), p.768-774
• Main Authors: Vintaikin, B. E., Smirnov, A. E., Shevchenko, S. Yu, Cherenkova, S. A.
• Format: Article
• Language: English
• Subjects: Alloys; Aluminum base alloys; Aluminum compounds; Chemistry and Materials Science; Chromium nitride; Diffusion; Glow discharges; Intermetallic phases; Lattice parameters; Materials Science; Mathematical analysis; Metallic Materials; Nickel aluminides; Nitriding; Phase Transformations; Scanning microscopy; Solid solutions; Specialty metals industry; Structure; Surface layers
• ISSN: 0031-918X; 1555-6190
• DOI: 10.1134/S0031918X22080166

The methods of X-ray diffractometry supplemented by mathematical methods to improve the resolution of X-ray patterns and the methods of scanning microscopy were applied to study the peculiarities of the structure of subsurface layers of Ni–40% Cr–3.5% Al alloy before and after nitriding in a glow discharge at 540°С; the compositions of the microregions were determined. Before nitriding, after quenching, and after aging, the main phases are the γ-Ni and α-Cr based solid solutions, a small amount of Ni 3 Al phase occurs, whose volume fraction increases after aging. It has been established that nitriding leads to the appearance of CrN and AlN phases in the surface layer and to a decrease in the amount of the Ni 3 Al phase. The micro-inhomogeneities of the phases based on the γ-Ni and α-Cr components are revealed; they are caused by differences in the interplane distances and lattice parameters.