Influence of electron beam additive manufacturing process features on the fine material structure of a nickel-based superalloy products.

In the present work the influence of technological parameters of wire-feed electron beam additive manufacturing on the size of γ'-phase precipitations the in the product of Ni-Al system of a heat-resistant nickel-based superalloy was investigated. It was shown that the size of γ'-phase precipitations in the form of nanoscale and submicrocrystalline cuboids in the material of the additively formed product was smaller than in the initial as-cast state. Depending on the distance to the substrate, the average size of cuboids ranged from 43 to 207 nm, which was 13 to 2.7 times smaller than in the as-cast state. It was found that, depending on the height of the additive product, the size of γ'-phase precipitations reached an extremum at a distance of about 20 mm to the substrate. The average size of γ'-phase cuboids did not exceed 133 nm in the final material layers of the additive product with a height of 34 mm. The extreme dependence of the size of γ'-phase precipitations along the height of the additive product was caused by a combination of a given monotonic decrease in the heat input and heat accumulation in the product material as it was being formed. [ABSTRACT FROM AUTHOR]