Direct Laser Fabrication process with coaxial powder projection of 316L steel. Geometrical characteristics and microstructure characterization of wall structures

Cheikh, Hussam El; Courant, Bruno; Branchu, Samuel; Huang, Xiaowei; Hascoët, Jean-Yves; Guillén, Ronald

doi:10.1016/j.optlaseng.2012.07.002

Cited by 62 publications

(22 citation statements)

References 18 publications

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“…These fine sub-grain microstructures and fine distribution of particular elements are confirmed beneficial to the alloy’s hardness, strength, ductility (known as defect-tolerant) [14,25], and thermal conductivity performance under some circumstances [26]. This kind dynamical formation of three-dimensional arrays of cells and bands structures are also very common in high energy beam material processing and rapid solidification, e.g., welding [27,28,29,30], surface melting [31,32,33], space directional solidification [34,35], laser cladding or laser engineered shaping (LENSTM) [36,37,38,39,40]. These technologies have common features with SLM of constrained crystal growth, so the similar microstructures can be fabricated.…”

Section: Introductionmentioning

confidence: 99%

Morphological Development of Sub-Grain Cellular/Bands Microstructures in Selective Laser Melting

Liu

Zhou

et al. 2019

Materials

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In this paper, single-layer and bulk 316 L selective laser melting (SLM) experiments were conducted, fine submicron-scale geometric symmetrical cellular (hexagonal, pentagonal and square), elongated cellular and bands solidification morphologies were found in the laser-melt top surface. Meanwhile, morphological developed sub-grain patterns with quasi-hexagonal cellular, elongated cellular and bands structures (size ~1 μm) coexisting inside one single macro-solidified grain were also identified. This demonstrated the transitions from quasi-hexagonal-cells to elongated cells/bands, and transitions reverse, occurred in the whole bulk under some circumstances during SLM. Based on the experimental realities, these morphologies are formed by the local convection and Bénard instabilities in front of the solid/liquid interface (so-called mushy zones) affected by intricate temperature and surface tension gradients. Quasi-hexagonal cellular convective fields are then superimposed on macro-grain solidification to form the sub-grain patterns and micro-segregations. This explanation seems reasonable and is unifying as it can be expanded to other eutectic alloys with face center cubic (FCC) prevenient phase prepared by SLM, e.g., the Al-Si and Co-Cr-Mo systems.

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Section: Introductionmentioning

confidence: 99%

Morphological Development of Sub-Grain Cellular/Bands Microstructures in Selective Laser Melting

Liu

Zhou

et al. 2019

Materials

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“…It was shown that the range of processing parameters is rather narrow for the production of samples with dimensional stability and microstructure integrity. El Cheikh et al [ 2 ] investigated the process of the direct laser fabrication (DLF) of products made of 316 L steel, studying, for example, the effect on the laser spot speed and the different laser shift-distances between two successive layers. Interactions between the process parameters were found.…”

Section: Introductionmentioning

confidence: 99%

On the Features of Composite Coating, Based on Nickel Alloy and Aluminum–Iron Bronze, Processed by Direct Metal Deposition

et al. 2021

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In recent years, additive manufacturing technologies have become increasingly widespread with the most intensive development being direct metal deposition (DMD), alloys, and ceramic materials on a metal substrate. This study shows the possibilities of the effective formation of coatings, based on heterogeneous metal alloys (Ni-based alloy and Fe-Al bronze) deposited onto 1045 structural steel. Changes in the microhardness, the microstructure, and the tribological properties of the composite coating, depending on the laser spot speed and pitch during DMD processing, have been considered. It was revealed that if the components of the composite coating are chosen correctly, there are possible DMD conditions ensuring reliable and durable connection between them and with the substrate.

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“…The vertically deposited single clad is normally considered to be a fundamental pillar for obtaining the map of process parameters, as shown in the work of de Oliveira et al [12]. The objective is to select one or more conditions for further studies of the overlap clad, as done in previous works using Eutroloy 16606A as a filler material [13] and by laser cladding of multilayer walls reported by El Cheikh et al [14] and Arregui et al [15]. However, there is no viable experimental argument for rejecting single clad parameters that are based on overlap percentages or multilayer structures.…”

Section: Introductionmentioning

confidence: 99%

Strategy Development for the Manufacturing of Multilayered Structures of Variable Thickness of Ni-Based Alloy 718 by Powder-Fed Directed Energy Deposition

Ramiro

Ortiz

Alberdi

et al. 2020

Metals

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In this study, a manufacturing strategy, and guidelines for inclined and multilayered structures of variable thickness are presented, which are based on the results of an own-developed geometrical model that obtains both the coating thickness and dilution. This model is developed for the powder-fed directed energy deposition process (DED) and it only uses the DED single-track cladding characteristics (height, width, area, and dilution depth), the overlap percentage, and the laser head tilting-angle as inputs. As outputs, it calculates both the cladding geometry and the dilution area of the coating. This model for the Ni-based alloy 718 was improved, based on previous studies of the single clad working both vertically and at an inclined angle, adding the equations of the single clad characteristics with respect to the main process parameters. The strategy proposed in this paper for multilayered cladding consisted of both adding an extra clad at the edges of the layer and using a variable value of the overlap percentage between clads for geometric adaptations. With this strategy, the material deposition is more accurate than otherwise, and it shows stable growth. Manufacturing a multilayered wall of wider thicknesses at higher heights was utilized to validate the strategy.

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Direct Laser Fabrication process with coaxial powder projection of 316L steel. Geometrical characteristics and microstructure characterization of wall structures

Cited by 62 publications

References 18 publications

Morphological Development of Sub-Grain Cellular/Bands Microstructures in Selective Laser Melting

Morphological Development of Sub-Grain Cellular/Bands Microstructures in Selective Laser Melting

On the Features of Composite Coating, Based on Nickel Alloy and Aluminum–Iron Bronze, Processed by Direct Metal Deposition

Strategy Development for the Manufacturing of Multilayered Structures of Variable Thickness of Ni-Based Alloy 718 by Powder-Fed Directed Energy Deposition

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