For this work, the behavior of the ZhS6K alloy (Russian grade) in the process of direct laser deposition was investigated. Two samples, a “small” one (40 × 10 × 10 mm³) and “large” one (80 × 16 × 16 mm³), were fabricated with direct laser deposition. In both samples, the typical dual-phase γ/γ’ microstructure with cuboidal shape of the γ’ precipitates was observed. Both specimens revealed a similar tendency to continuous increasing in hardness from the bottom to the top associated with the refinement of γ’ precipitates. The “small” sample was essentially crack-free, while the “large” one underwent extensive cracking. The possible effects of various factors, including thermal history, size, and shape of the gamma grains, on cracking behavior were discussed.

This article deals with the theoretical issues of the formation of a melt pool during the process of direct laser deposition. The shape and size of the pool depends on many parameters, such as the speed and power of the process, the optical and physical properties of the material, and the powder consumption. On the other hand, the influence of the physical processes occurring in the material on one another is significant: for instance, the heating of the powder and the substrate by laser radiation, or the formation of the free surface of the melt, taking into account the Marangoni effect. This paper proposes a model for determining the size of the melt bath, developed in a one-dimensional approximation of the boundary layer flow. The dimensions and profile of the surface and bottom of the melt pool are obtained by solving the problem of convective heat transfer. The influence of the residual temperature from the previous track, as well as the heat from the heated powder of the gas–powder jet, taking into account its spatial distribution, is considered. The simulation of the size and shape of the melt pool, as well as its free surface profile for different alloys, is performed with 316 L steel, Inconel 718 nickel alloy, and VT6 titanium alloy

Direct laser deposition (DLD) is a promising additive technology that allows for the rapid and cheap production of metal parts of complex geometry in various sectors of mechanical engineering. Thick-walled metal structures occupy a significant part in mechanical engineering. The purpose of this study was to develop and test an algorithm for predicting the geometry of deposited multi-pass walls. To achieve this goal, the main interrelated processes involved in the formation of a multi-pass wall were described—the process of laser radiation propagation, the process of heat transfer and the process of bead formation. To construct the calculation algorithm, five characteristic types of beads are identified. For these five types, the features of the bead formation and the features of the laser radiation intensity distribution are described. The calculated data were verified. A good match of the calculated data with the geometry of the deposited walls from AISI321 steel, Inconel718 and Ti-6Al-4V alloys was obtained.

Effective application of hybrid laser technologies can help to decide the problem of creating high-performance welding technologies that allow to optimize the process of producing critical structures, as well as to reduce labor intensiveness material consumption. Today the development of industrial technologies for the manufacture of extended body parts under minimum tolerance condition requires the numerical simulation of thermal deformation processes occurring in the material during welding and affecting the final operating characteristics of products. The article is devoted to the search for the optimal solution of the problem of determining the T-joint geometrics, taking into account the possibility varying the positional relationship of the laser and arc heat sources on both sides. The thermal field that is created by two simultaneously operating combined heat sources is one of the key parameters of the process.

Additive manufacturing provides a flexible processing route for fabricating Ni3Al-based intermetallics with controlled geometry, microstructure, and properties. However, secondary-phase formation during Ni3Al synthesis appears difficult to suppress and remains insufficiently understood. In this work, laser-based directed energy deposition (DED-LB) from a mixture of elemental Ni and Al powders was used to fabricate a Ni3Al-based intermetallic and clarify the origin of secondary phase formation. By varying the processing parameters, a deposition window for obtaining defect-free Ni3Al was established. Structural analysis revealed that B2-NiAl and orthorhombic Ni5Al3 secondary phases are heterogeneously distributed within the γ′-Ni3Al matrix with an ordered L12 structure. The compositions of γ′-Ni3Al and Ni5Al3 were ⁓Ni75.1Al24.9 and Ni64.7Al35.3, respectively. Phase mapping showed that the fraction of B2-NiAl varied from ⁓1.1% in the bottom region to ⁓0.5% in the middle region and ⁓1.1% in the top region, whereas the fraction of Ni5Al3 increased from ⁓0.8% to ⁓2.5% and ⁓3.8%, respectively. Nanoindentation mapping revealed an average hardness of ⁓2.1 GPa, with no clear correlation between the hardness and secondary-phase distribution. The temperature-time histories of individual layers extracted from simulated thermal cycles constrain the possible transformation scenarios and identify the B2-NiAl → L10 martensite → Ni5Al3 sequence as the most plausible transformation pathway. By linking thermal history to phase composition in DED-LB-processed Ni3Al, this work provides a framework for understanding and controlling formation of secondary phases in additively manufactured Ni-Al intermetallics.

Additive manufacturing provides a flexible processing route for fabricating Ni3Al-based intermetallics with controlled geometry, microstructure, and properties. However, secondary-phase formation during Ni3Al synthesis appears difficult to suppress and remains insufficiently understood. In this work, laser-based directed energy deposition (DED-LB) from a mixture of elemental Ni and Al powders was used to fabricate a Ni3Al-based intermetallic and clarify the origin of secondary phase formation. By varying the processing parameters, a deposition window for obtaining defect-free Ni3Al was established. Structural analysis revealed that B2-NiAl and orthorhombic Ni5Al3 secondary phases are heterogeneously distributed within the γ′-Ni3Al matrix with an ordered L12 structure. The compositions of γ′-Ni3Al and Ni5Al3 were ⁓Ni75.1Al24.9 and Ni64.7Al35.3, respectively. Phase mapping showed that the fraction of B2-NiAl varied from ⁓1.1% in the bottom region to ⁓0.5% in the middle region and ⁓1.1% in the top region, whereas the fraction of Ni5Al3 increased from ⁓0.8% to ⁓2.5% and ⁓3.8%, respectively. Nanoindentation mapping revealed an average hardness of ⁓2.1 GPa, with no clear correlation between the hardness and secondary-phase distribution. The temperature-time histories of individual layers extracted from simulated thermal cycles constrain the possible transformation scenarios and identify the B2-NiAl → L10 martensite → Ni5Al3 sequence as the most plausible transformation pathway. By linking thermal history to phase composition in DED-LB-processed Ni3Al, this work provides a framework for understanding and controlling formation of secondary phases in additively manufactured Ni-Al intermetallics.