Microstructure and Phase Composition of Ni–Cr–Al-Based Intermetallics Obtained by a Dual-Wire Electron Beam Additive Manufacturing

Abstract

Additive manufacturing (3D printing) is one of the most promising methods for creating complex metal parts and structures. It has already become a widespread industrial method in the production of coatings or various details of constructions and mechanisms made of pure metals and alloys. In this work, the mechanisms of the formation of intermetallic compounds based on nickel, aluminum and chromium by a dual-wire electron beam additive manufacturing were studied. The microstructure, phase composition, and microhardness of the intermetallic material strongly depend on the ratio of NiCr and Al wires deposited during the electron-beam melting. The intermetallic material based on the NiAl phase was obtained by the deposition of wires in the equal ratio NiCr:Al = 1:1. In the material obtained with a wire ratio of NiCr:Al = 3:1, ordered Ni₃Al(Cr) and disordered Ni₃Cr(Al) intermetallic compounds are predominantly observed, but the fraction of the Ni₃Cr-based phase prevails. The microhardness of the NiAl-based alloy turns out to be higher (5.1 GPa) than that of the Ni₃Al(Cr)-based material (4.3 GPa). These intermetallic alloys are developed for the production of intermetallic coatings using electron beam additive manufacturing method.