Effect of hatch length on the development of microstructure, texture and residual stresses in selective laser melted superalloy Inconel 718

Nadammal, Naresh; Cabeza, Sandra; Mishurova, Tatiana; Thiede, Tobias; Kromm, Arne; Seyfert, Christoph; Farahbod, L.; Haberland, Christoph; Schneider, Judith; Portella, Pedro Dolabella; Bruno, Giovanni

doi:10.1016/j.matdes.2017.08.049

Cited by 229 publications

(75 citation statements)

References 42 publications

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“…A strong epitaxy is observed with columnar grains in red (< 001 > // BD) and green (< 011 > // BD) crossing most of the layers. However, contrary to previous study made by Nadammal et al (2017), those red < 001 > columnar grains are not localized at overlapping melt pools, but at the center of vertically aligned melt pools. The same observation had already been made by Thijs et al(2013).…”

Section: Ebsd Grain Characterizationcontrasting

confidence: 98%

“…Thijs et al (2013) observed a < 001 > fiber texture in AlSi10Mg along the laser scanning direction, which was described further by Liu and To (2017) with a semi-empirical model. Nadammal et al (2017) identified a strong {110} < 001 > Goss texture in Inconel 718. Sun et al (2018) observed that the scanning strategy could deeply impact the resulting texture orientation in a Ni-25%Mo alloy.…”

Section: Introductionmentioning

confidence: 99%

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Texture control of 316L parts by modulation of the melt pool morphology in selective laser melting

Andreau

Koutiri

Peyre

et al. 2019

Journal of Materials Processing Technology

301

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A B S T R A C TIn this study, 316L parts were fabricated with the selective laser melting additive layer manufacturing process using unidirectional laser scan to control their texture. The melt pool shape, microstructure and texture of three different cubic samples were analyzed and quantified using optical microscopy and electron back-scattered diffraction. The samples scanned along the shielding gas flow direction were shown to exhibit shallow conduction melt pools together with a strong {110} < 001 > Goss texture along the laser scanning direction. The sample prepared with a laser scan perpendicular to the gas flow direction had deeper melt pools, with a weaker {110} < 001 > Goss texture in addition to a < 100 > fiber texture parallel to the scanning direction. Correlations were proposed between the melt-pool geometry and overlap and the resulting texture. The decrease of the melt pool depth was assumed to be linked to local attenuation of the laser beam effective power density transmitted to the powder bed.

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Section: Ebsd Grain Characterizationcontrasting

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Texture control of 316L parts by modulation of the melt pool morphology in selective laser melting

Andreau

Koutiri

Peyre

et al. 2019

Journal of Materials Processing Technology

301

View full text Add to dashboard Cite

show abstract

“…Residual stresses and strains are inherently linked to the processing conditions. For the laser powder bed fusion (LPBF) process, the thermal gradients, cooling rates, and part mechanical constraints result in the multi lengthscale residual stresses that exist within the as-built part [1][2][3][4][5]. These stresses can affect the component life in service and cause a catastrophic failure during the build such as part separation from the build plate.…”

Section: Introductionmentioning

confidence: 99%

Elastic Residual Strain and Stress Measurements and Corresponding Part Deflections of 3D Additive Manufacturing Builds of IN625 AM-Bench Artifacts Using Neutron Diffraction, Synchrotron X-Ray Diffraction, and Contour Method

Phan

Strantza

Hill

et al. 2019

Integr Mater Manuf Innov

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“…Nadammal et al [37] studied the scan vector length influence on RS by neutron diffraction of IN718 parts fabricated by PBF-LB. Constant compressive stresses from approximately 200 to 400 MPa were measured in specimens built with short scan vectors, mainly in the build direction.…”

Section: Introduction Of Intermetallic Compounds and Metal Matrix Commentioning

confidence: 99%

Laser Powder Bed Fusion of Inconel 718: Residual Stress Analysis Before and After Heat Treatment

Barros

Silva

Gouveia

et al. 2019

Metals

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Residual stresses (RS) of great magnitude are usually present in parts produced by Laser Powder Bed Fusion (PBF-LB), mainly owing to the extreme temperature gradients and high cooling rates involved in the process. Those "hidden" stresses can be detrimental to a part's mechanical properties and fatigue life; therefore, it is crucial to know their magnitude and orientation. The hole-drilling strain-gage method was used to determine the RS magnitude and direction-depth profiles. Cuboid specimens in the as-built state, and after standard solution annealing and ageing heat treatment conditions, were prepared to study the RS evolution throughout the heat treatment stages. Measurements were performed on the top and lateral surfaces. In the as-built specimens, tensile stresses of~400 MPa on the top and above 600 MPa on the lateral surface were obtained. On the lateral surface, RS anisotropy was noticed, with the horizontally aligned stresses being three times lower than the vertically aligned. RS decreased markedly after the first heat treatment. On heat-treated specimens, magnitude oscillations were observed. By microstructure analysis, the presence of carbides was verified, which is a probable root for the oscillations. Furthermore, compressive stresses immediate to the surface were obtained in heat-treated specimens, which is not in agreement with the typical characteristics of parts fabricated by PBF-LB, i.e., tensile stresses at the surface and compressive stresses in the part's core.Diverse metals AM techniques exist, and the most adopted in the industry are Powder Bed Fusion (PBF) and Directed Energy Deposition (DED), as for the classification by the ISO/ASTM 52900 (2015) international standard. These two techniques use a laser or an electron beam as a high energy density source to selectively melt the material and build the parts [3][4][5][6][7]. Actually, different nomenclatures are used for the same process. Laser Powder Bed Fusion (PBF-LB) is also known as Selective Laser Melting (SLM), Direct Metal Laser Sintering (DMLS), and Laser Cusing [7,8,11], depending mostly on the AM systems supplier.Focusing on PBF-LB, a micro-size powder is spread in thin layers of 20 and 50 µm [3], and then a laser beam guided by a galvanometric mirror selectively melts the deposited material according to the CAD model. The parts are built progressively from bottom to top, also known as the building direction (vertical) [7,11]. The use of support structures is common, either to support down-facing surfaces or to prevent part distortion. Part distortion occurs due to the large residual stresses (RS) generated during material solidification layer-by-layer, owing to the extreme temperature gradients and high cooling rates [12].New feedstock materials dedicated to AM systems have been developed; thereby, new opportunities will arise in the near future of AM [13]. Stainless steel; tool steel; and Ni-, Al-, Ti-, Co-Cr-, and Cu-based alloys are just a few of the metallic materials currently available for AM [7,14,15]. Introduction of int...

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Effect of hatch length on the development of microstructure, texture and residual stresses in selective laser melted superalloy Inconel 718

Cited by 229 publications

References 42 publications

Texture control of 316L parts by modulation of the melt pool morphology in selective laser melting

Texture control of 316L parts by modulation of the melt pool morphology in selective laser melting

Elastic Residual Strain and Stress Measurements and Corresponding Part Deflections of 3D Additive Manufacturing Builds of IN625 AM-Bench Artifacts Using Neutron Diffraction, Synchrotron X-Ray Diffraction, and Contour Method

Laser Powder Bed Fusion of Inconel 718: Residual Stress Analysis Before and After Heat Treatment

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