Fabrication of Narrow-Fraction Micropowders of NiAl-Based Refractory Alloy CompoNiAl-M5-3

Abstract

Powders of new CompoNiAl M5-3 heat-resistant alloy were prepared by mechanoactivated SHS from (Ni–Al–Cr–Co–Hf)–NaCl mixtures. Ni dissolution in Al melt was found to be the motive force of combustion. Unlike the binary Ni–Al system, NiAl is formed not in the melt but in the post-combustion zone as a result of diffusion-controlled processes. Conditions for MASHS were optimized toward fabrication of a superalloy with homogeneous composition/structure and low content of gas impurities. As-prepared combustion product was disintegrated into a powder and the latter was subjected to plasma spheroidization, keeping in mind the needs of additive manufacturing. The attained degree of spheroidization was 98%. The structure and phase/chemical compositions of spherical powders did not differ from those of the synthesized powders. After plasma treatment, the content of gas impurities (О₂ and N₂) decreased.