ANISOTROPY OF MICROSTRUCTURE AND PROPERTIES OF SLM ALLOY INCONEL 718
DOI:
https://doi.org/10.20535/kpisn.2025.3.333074Keywords:
selective laser melting, Inconel 718, microstructure, phase composition, texture, stressAbstract
Background. The use of additive technologies, in particular selective laser melting (SLM), opens up new opportunities for the manufacture of parts with complex geometric shapes. However, the specifics of the 3D printing process cause a number of technological problems. Research into the mechanisms of microstructural evolution during SLM is necessary to optimize technological modes and ensure reliable and long-term operation of printed products in various industries.
Objective. Determination of microstructure features and microhardness distribution in different planes of the Inconel 718 SLM alloy, as well as comparative analysis of phase composition, texture, and macroscopic stress level.
Methods. A complex of techniques was applied - metallography, scanning electron microscopy, microdurometric and X-ray phase analysis.
Results. The anisotropy of the microstructure of the SLM alloy Inconel 718, which is formed during 3D printing as a result of sequential solidification of melt pools, has been identified and characterized. Significant variability of microhardness values in different planes has been shown as a consequence of the anisotropy of the structure and phase composition.
Conclusions. The amount of the main γ-phase and the strengthening γ′- and γ″-phases, as well as NbC carbide, is determined. Factors affecting the anisotropy of residual stresses and texture are discussed, including the direction of heat flow, cooling rate, reheating of layers, and the orientation of the grains formed.
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