Functionally graded Inconel 718 processed by additive manufacturing: Crystallographic texture, anisotropy of microstructure and mechanical properties

Popovich, Vera; Борисов, Е. В.; Popovich, Anatoly; Sufiiarov, Vadim; Masaylo, Dmitriy; Alzina, L.

doi:10.1016/j.matdes.2016.10.075

Cited by 423 publications

(133 citation statements)

References 20 publications

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“…The γ-phase matrix composition is consistent with the literature [4,13,30]. Wang et al [4] detected a needle-like δ phase with a rhombic crystal structure and (Ni 3 Nb) atomic formula in solution-treated SLM Inconel 718 followed by double aging.…”

Section: Phase Analysis Of Heat-treated Inconel 718supporting

confidence: 87%

“…Grain growth over melt pool boundaries is due to the remelting of previous layers at the bottom of the specimen [30]. Columnar grains crossing over melt pool boundaries are also observed in locations 1 and 2 of Figure 4.…”

Section: Microstructure Of the As-printed Inconel 718mentioning

confidence: 88%

“…The observed difference in mechanical properties was attributed to a strong (001) texture and the coarser grains in the specimens fabricated by higher laser power [30]. The average Vickers hardness measurements are displayed in Table 4.…”

Section: Vickers Microhardness Measurementsmentioning

confidence: 99%

“…Popovich et al [30] reported that SLM IN718 specimens fabricated at lower laser power (250 W) had a higher average hardness of 320 HV compared to 287 HV for those fabricated at higher laser power (900 W) while volumetric energy density was held constant. The observed difference in mechanical properties was attributed to a strong (001) texture and the coarser grains in the specimens fabricated by higher laser power [30].…”

Section: Vickers Microhardness Measurementsmentioning

confidence: 99%

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Microstructural and Microhardness Evolution from Homogenization and Hot Isostatic Pressing on Selective Laser Melted Inconel 718: Structure, Texture, and Phases

Seede

Mostafa

Braïlovski

et al. 2018

JMMP

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Abstract:In this work, the microstructure, texture, phases, and microhardness of 45 • printed (with respect to the build direction) homogenized, and hot isostatically pressed (HIP) cylindrical IN718 specimens are investigated. Phase morphology, grain size, microhardness, and crystallographic texture at the bottom of each specimen differ from those of the top due to changes in cooling rate. High cooling rates during the printing process generated a columnar grain structure parallel to the building direction in the as-printed condition with a texture transition from (001) orientation at the bottom of the specimen to (111) orientation towards the specimen top based on EBSD analysis. A mixed columnar and equiaxed grain structure associated with about a 15% reduction in texture is achieved after homogenization treatment. HIP treatment caused significant grain coarsening, and engendered equiaxed grains with an average diameter of 154.8 µm. These treatments promoted the growth of δ-phase (Ni 3 Nb) and MC-type brittle (Ti, Nb)C carbides at grain boundaries. Laves phase (Fe 2 Nb) was also observed in the as-printed and homogenized specimens. Ostwald ripening of (Ti, Nb)C carbides caused excessive grain growth at the bottom of the HIPed IN718 specimens, while smaller grains were observed at their top. Microhardness in the as-fabricated specimens was 236.9 HV and increased in the homogenized specimens by 19.3% to 282.6 HV due to more even distribution of secondary precipitates, and the nucleation of smaller grains. A 36.1% reduction in microhardness to 180.5 HV was found in the HIPed condition due to γ phase dissolution and differences in grain morphology.

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Section: Phase Analysis Of Heat-treated Inconel 718supporting

confidence: 87%

Section: Microstructure Of the As-printed Inconel 718mentioning

confidence: 88%

Section: Vickers Microhardness Measurementsmentioning

confidence: 99%

Section: Vickers Microhardness Measurementsmentioning

confidence: 99%

See 2 more Smart Citations

Microstructural and Microhardness Evolution from Homogenization and Hot Isostatic Pressing on Selective Laser Melted Inconel 718: Structure, Texture, and Phases

Seede

Mostafa

Braïlovski

et al. 2018

JMMP

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“…As regarding LPBF, anisotropy has been discussed in the literature for stainless steel [21,22], titanium [23], and Ni-based alloys [24,25]; anisotropy has also been reported when AM is conducted by means of electron beam [26]. This issue is expected to be crucial for Ni-based superalloys which are highly anisotropic and are conveniently processed to the purpose of producing functionally graded components [27], indeed. Interestingly, higher strength compared to the casted counterpart has been reported for IN738LC parts, whilst less significant differences have been shown at elevated temperature [25].…”

Section: Introductionmentioning

confidence: 99%

Laser powder-bed fusion of Inconel 718 to manufacture turbine blades

Caiazzo

Alfieri

Corrado

et al. 2017

Int J Adv Manuf Technol

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In the frame of additive manufacturing of metals, laser powder-bed fusion is investigated in this paper as an advanced industrial prototyping tool to manufacture Inconel 718 turbine blades at a predesign stage before flow production. Expediting of the evaluation of any upgrade to the part is aimed. To this purpose, possible anisotropy of manufacturing is preliminarily investigated via tensile testing at room and elevated temperature as a function of the sloping angle with the building plate; the normalized strength is given and compared with similar studies in the literature. Positioning and proper supporting in manufacturing are discussed; the parts are further investigated to assess their compliance with the intended nominal geometry.

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Solution Treatment Study of Inconel 718 Produced by SLM Additive Technique in View of the Oxidation Resistance

et al. 2018

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The additive manufacturing concept for the production of complex near net shape metal parts is obtaining increasing attention due to the possibility of producing assembled and/or complex parts allowing optimal design and saving time and cost. The possibility to use the free design of Selective Laser Melting (SLM) techniques for the fabrication of complex 3D components using high performing, although difficult to work, materials such as Ni superalloys is really attractive. The particular process conditions that are established during additive manufacturing in SLM leads to microstructures different with respect to those observed in standard cast or wrought analogous material. Therefore, it is usually necessary to apply a post solution treatment, in order to reduce the segregation of heavier elements (in particular Nb) and dissolve the interdendritic precipitates. In this study, the influence of temperature and time of the solution treatment on the microstructure is investigated in order to find the best results in terms of the final oxidation resistance. Oxidation performances of solutioned Inconel 718 fabricated via SLM are reported and discussed. The growth rate of the superficial oxide at the temperature of 850 C was measured and the longterm stability of this passivating layer was tested until 908 h.

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Functionally graded Inconel 718 processed by additive manufacturing: Crystallographic texture, anisotropy of microstructure and mechanical properties

Cited by 423 publications

References 20 publications

Microstructural and Microhardness Evolution from Homogenization and Hot Isostatic Pressing on Selective Laser Melted Inconel 718: Structure, Texture, and Phases

Microstructural and Microhardness Evolution from Homogenization and Hot Isostatic Pressing on Selective Laser Melted Inconel 718: Structure, Texture, and Phases

Laser powder-bed fusion of Inconel 718 to manufacture turbine blades

Solution Treatment Study of Inconel 718 Produced by SLM Additive Technique in View of the Oxidation Resistance

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