1. Influence of laser beam shape and post heat-treatment on the microstructure and mechanical properties of nickel-based alloy IN718 manufactured by laser powder bed fusionMatjaž Godec, Narges Mirzabeigi, Črtomir Donik, Danijela Anica Skobir Balantič, Simon Malej, Irena Paulin, Bojan Podgornik, Jonas Grünewald, Tobias Novotny, Florian Bayer, Francisco Ruiz-Zepeda, Katrin Wudy, 2025, original scientific article Abstract: This study examines the effect of Gaussian and ring-shaped laser beam profiles on the microstructural development and mechanical properties of the PBF-LB/M processed nickel-based alloy Inconel 718 in its as-built and post-heat-treated conditions. Beam shaping was employed to achieve a faster build rate without compromising material properties. One of the objectives was to optimise heat treatment conditions for the beam-shaped profile. The post-heat-treatment process included four different solution annealing temperatures (954 °C, 984 °C, 1034 °C and 1154 °C), followed by two-step ageing, respectively. The microstructure evolution was revealed using scanning electron microscopy (SEM) equipped with energy-dispersive X-ray diffraction (EDS). The mechanical properties in all investigated conditions were evaluated based on tensile tests at room temperature. Using a Gaussian laser beam profile results in a fine-grained microstructure without a strong columnar orientation, while the ring beam profile produces a distinct columnar structure with larger nanodendritic grains and dislocation cells. Both beam profiles exhibit a similar proportion of Laves phase. After post-heat treatment, the Gaussian beam profile generally provides 3-7 % higher mechanical properties. The differences in mechanical properties between horizontal and vertical building directions are greater for ring-shaped laser beam profiles. Heat-treatment temperature above 1034 °C leads to recrystallisation, grain growth and the formation of carbonitrides which reduce mechanical properties. Based on the results, the proposed optimal heat-treatment temperature for both investigated laser beam shapes is 984 °C. At this temperature, tensile strength equalises between horizontal and vertical build directions while yield strength increases, which is beneficial for most applications.
Keywords: PBF-LB/M, beam shaping, IN718, heat treatment, mechanical properties
Published in DiRROS: 07.07.2025; Views: 37; Downloads: 10
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2. Comparison of powder-bed fusion, directed-energy deposition and hybrid additive manufacturing of Ti6Al4V components: microstructure, corrosion and mechanical propertiesAleksandra Kocijan, Simon Malej, 2025, original scientific article Keywords: additive manufacturing, Ti6Al4V, microstructure, corrosion, mechanical properties
Published in DiRROS: 10.04.2025; Views: 234; Downloads: 115
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7. Characterisation of the microstructure and defects during the direct energy deposition of hybrid Ti6Al4V in a low-quality atmosphereSimon Malej, Črtomir Donik, Matej Balažic, Matija Bizjak, Marko Kač, Matjaž Godec, 2023, original scientific article Keywords: direct energy deposition, Ti6Al4V, protective atmosphere
Published in DiRROS: 08.03.2024; Views: 791; Downloads: 419
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8. Hybrid additive manufacturing of Ti6Al4V with powder-bed fusion and direct-energy depositionSimon Malej, Matjaž Godec, Črtomir Donik, Matej Balažic, René Zettler, Thomas Lienert, Laurent Pambaguian, 2023, original scientific article Keywords: hybrid additive manufacturing, Ti6Al4V, tensile properties, defects, microstructure, phase transformation
Published in DiRROS: 02.02.2024; Views: 1103; Downloads: 469
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