An as-cast macrostructure of electron beam additively manufactured metallic materials was represented by coarse columnar grains whose axes were inclined at 25° with respect to the substrate’s plane. One part of the as-grown samples was annealed to form a coarse grain microstructure while the other part was pre-deformed by forging and then annealed what allowed obtaining recrystallized microstructures with small grains and multiple annealing twin boundaries. This sample showed both high strength and plasticity during the tensile tests. These tensile tests demonstrated also two-stage stress-strain curves as depended on their strain hardening rates. High and low strain hardening rates corresponded to a twinning-dominated deformation at stage II and dislocation-base deformation at stage III. A submicron size strain-induced grain-subgrain microstructure was formed in the vicinity of a necked zone as a result of combined twinning/dislocation grain refining.

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Electron beam additive wire-feed deposition of Cu-7.5wt.%Al bronze on a stainless-steel substrate has been carried out at heat input levels 0.21, 0.255, and 0.3 kJ/mm. The microstructures formed at 0.21 kJ/mm were characterized by the presence of both zigzagged columnar and small equiaxed grains with 10% of Σ3 annealing twin grain boundaries. No equiaxed grains were found in samples obtained at 0.255 and 0.3 kJ/mm. The zigzagged columnar ones were only retained in samples obtained at 0.255 kJ/mm. The fraction of Σ3 boundaries reduced at higher heat input values to 7 and 4%, respectively. The maximum tensile strength was achieved on samples obtained with 0.21 kJ/mm as tested with a tensile axis perpendicular to the deposited wall’s height. More than 100% elongation-to-fracture was achieved when testing the samples obtained at 0.3 kJ/mm (as tested with a tensile axis coinciding with the wall’s height).

Electron beam additive wire-feed manufacturing of Cu-3wt.%S-0.8wt.%Mn bronze thin wall on a stainless steel substrate has been carried out at heat input levels of 0.19, 0.25, and 0.31 kJ/mm. The microstructures of as-deposited metal ranged from low aspect ratio columnar with equiaxed grain layers to zig-zagged and high aspect ratio columnar, as depended on the heat input. Post-deposition annealing at 900 °C for 6 h resulted in recrystallization of the high aspect ratio columnar grains with further grain growth by boundary migration. Pre-deformation by 10% thickness reduction and then annealing at 900 °C for 6 h also allowed obtaining recrystallized grain structures with less fraction of twin boundaries but higher fraction of high-angle ones, as compared to those of only annealed sample. Pre-deformation and ensuing annealing allowed simultaneous increasing of the ultimate tensile strength and strain-to-fracture.

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In the present study, a microstructural investigation of wire-feed EBAM-manufactured nickel-based and titanium-based alloys were conducted by producing single wall sample with 16 and 19 vertical layers, respectively. It was shown that in obtained material microstructural and elemental gradient presents. The results of the research show that dendrites and grains grow epitaxial in the direction of temperature gradient. Non-directional dissipation of heat on the edge of the sample leads to formation of equiaxed structure. Chosen parameters allow to produce low-defective samples by EBAM technology.

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