Microstructure characterization of recycled IN718 powder and resulting laser clad material

Renderos, Mario; Torregaray, A.; Gutiérrez-Orrantia, M.E.; Lamíkiz, Aitzol; Saintier, Nicolas; Girot, F.

doi:10.1016/j.matchar.2017.09.029

Cited by 46 publications

(12 citation statements)

References 19 publications

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“…An increasing oxygen content in the AM fabricated material has, however, been identified as a limiting factor for the permitted number of re-use cycles, due to the resulting reduction in component ductility. [11] For Ti-6Al-4V, which is the most widely studied material for EBM, it has been shown that the bulk oxygen level of powder as well as EBM fabricated material increases progressively along with powder recycling. [12][13][14] The main source of oxygen has in this case been described as adsorption of water on the powder surface during powder handling, grit blasting, and sieving, followed by a pick-up of oxygen during high-temperature exposure in the build chamber.…”

Section: Introductionmentioning

confidence: 99%

Effect of Powder Recycling in Electron Beam Melting on the Surface Chemistry of Alloy 718 Powder

Gruber

Henriksson

Hryha

et al. 2019

Metall Mater Trans A

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Process-induced degradation of the powder feedstock in additive manufacturing may have a negative influence on the final properties of built components. Consequently, it may lower the cost-effectiveness of powder bed additive manufacturing, which relies on recycling of the nonconsumed powder. This is especially the case for production of high-performance aero engine components where high material and process reliability is required. This study comprises a detailed investigation on the degradation of Alloy 718 powder during multicycle electron beam melting (EBM). The surface-sensitive analysis methods, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), were combined with scanning electron microscopy (SEM) to depict the differences in surface morphology, and surface composition of powder samples exposed to varying numbers of re-use cycles. The results show a significant change in surface characteristics after exposing the powder to the process and the environment in the build chamber. The virgin powder is covered mainly by a relatively thin and homogeneous oxide layer. The re-used powder, however, has undergone transformation to a heterogeneous oxide layer, rich in thermodynamically stable Al-rich oxide particulates, which started already during the first build cycle. Significant growth of the Al-rich oxide occurs via selective oxidation of Al under the conditions in the build chamber, including both pickup of oxygen from the process atmosphere and redistribution of initial surface-bound oxygen from less-stable products like Ni-oxide and/or hydroxide.

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Section: Introductionmentioning

confidence: 99%

Effect of Powder Recycling in Electron Beam Melting on the Surface Chemistry of Alloy 718 Powder

Gruber

Henriksson

Hryha

et al. 2019

Metall Mater Trans A

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“…These round pores (e.g., Figure 4a) form due to the injection of dissolved gas at the liquidsolid interface. Spherical pores typically have four different origins: (i) the moisture absorbed by the powder particles in the ambient atmosphere, (ii) shielding gas during the manufacturing process, (iii) gas entrapped inside the powder particles during the powder atomization process, and (iv) entrapment of the gas during the manufacturing process due to alloy vapors inside the molten pool [46,47]. Figure 4b shows an example of a large pore in Sample 2, which can be assumed to have formed due to keyhole collapse and shrinkage during L-PBF processing.…”

Section: Resultsmentioning

confidence: 99%

Mapping Spatial Distribution of Pores in an Additively Manufactured Gold Alloy Using Neutron Microtomography

et al. 2021

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A crucial criterion for the quality of the additively manufactured parts is the porosity content for achieving an acceptable final relative density. In addition, for jewelry applications, visible pores are unacceptable at or in the vicinity of the surface. In this study, non-destructive 3D neutron microtomography is applied to map the spatial distribution of pores in additively manufactured red-gold samples. The 3D imaging assessment underlines the high relative density of the printed red-gold sample and indicates residual pore sizes are predominantly below the limit of concern for jewelry applications. The 3D maps of pores within printed samples highlight the effect of the scanning strategy on the final quality and location of pores in the printed samples. These results confirm that neutron microtomography is a novel and precise tool to characterize residual porosity in additively manufactured gold alloys and other higher-Z materials where such investigation using other non-destructive methods (such as X-rays) is challenging due to the limited penetration depth.

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“…Renderos et al studied the microstructure on recycled Inconel 718 powder in DED [134] and concluded that powder particles maintained their morphological and chemical properties after crossing through the nozzle. The static mechanical properties of the recycled builds were found to be similar to those of the new powder builds for a limited recycling number (two times).…”

Section: Reusementioning

confidence: 99%

Study of the Environmental Implications of Using Metal Powder in Additive Manufacturing and Its Handling

Arrizubieta

Ukar

Ostolaza

et al. 2020

Metals

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Additive Manufacturing, AM, is considered to be environmentally friendly when compared to conventional manufacturing processes. Most researchers focus on resource consumption when performing the corresponding Life Cycle Analysis, LCA, of AM. To that end, the sustainability of AM is compared to processes like milling. Nevertheless, factors such as resource use, pollution, and the effects of AM on human health and society should be also taken into account before determining its environmental impact. In addition, in powder-based AM, handling the powder becomes an issue to be addressed, considering both the operator´s health and the subsequent management of the powder used. In view of these requirements, the fundamentals of the different powder-based AM processes were studied and special attention paid to the health risks derived from the high concentrations of certain chemical compounds existing in the typically employed materials. A review of previous work related to the environmental impact of AM is presented, highlighting the gaps found and the areas where deeper research is required. Finally, the implications of the reuse of metallic powder and the procedures to be followed for the disposal of waste are studied.2 of 25 sold in 2016 was 983, whereas, in the year 2017 this value rose to 1768 units, which implies an 80% increase [1].As far as economy and sustainability are concerned, AM offers several advantages over conventional manufacturing techniques, which confers many potential applications to AM in diverse industrial sectors, such as automotive, aerospace, biomedical, energy, and consumer goods [4]. In the aerospace industry, for example, AM enables aerospace motorists to create blades with much more complex internal cooling channels, allowing engines to run at higher temperatures and thus increase their performance [5]. In the report presented by the National Institute of Standards and Technology (NIST) of the U.S. Department of Commerce, it is stated that in aerospace engines titanium parts are machined down to size from large initial blocks, which leads to more than 90% waste material, material waste that could be reduced by using AM [6]. The European Commission in the Digital Transformation Monitor of 2017 presented similar numbers, where the disruptive nature of 3D printing was studied. It was estimated that by 2050, AM could save up to 90% of the raw material needed for manufacturing [3].Nonetheless, the possibilities of AM are not only limited to a reduction of raw material usage. The possibility of manufacturing lighter components could lead to energy savings, estimated between 5% and 25% by 2050, as well as a reduction in manufacturing costs of around 4-21% for the same period [7]. This trend is applicable to different industrial sectors. For example, SmarTech expects the overall market for AM in automotive to reach 5.3 billion USD in revenues by 2023 and to achieve 12.4 billion USD by 2028 [8].The lack of European and international standardization related to AM is proving to be an impediment to the...

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Microstructure characterization of recycled IN718 powder and resulting laser clad material

Cited by 46 publications

References 19 publications

Effect of Powder Recycling in Electron Beam Melting on the Surface Chemistry of Alloy 718 Powder

Effect of Powder Recycling in Electron Beam Melting on the Surface Chemistry of Alloy 718 Powder

Mapping Spatial Distribution of Pores in an Additively Manufactured Gold Alloy Using Neutron Microtomography

Study of the Environmental Implications of Using Metal Powder in Additive Manufacturing and Its Handling

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