Thermal stability of additively manufactured austenitic 304L ODS alloy

Ghayoor, Milad; Mirzababaei, Saereh; Sittiho, Anumat; Charit, Indrajit; Paul, Brian K.; Pasebani, Somayeh

doi:10.1016/j.jmst.2020.12.033

Cited by 31 publications

(5 citation statements)

References 49 publications

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“…35 More recent studies have experimented with varying the LPBF chamber atmosphere or the powder composition. 19,[36][37][38][39] While the reported data are promising, these studies highlight the need for tight control over the relative stoichiometry between oxygen and oxide formers within the LPBF melt pool. However, they are not conclusive with respect to how tightly the atmosphere must be controlled or the influence of subtle variations in local oxygen content on the oxide size, density distribution, and homogeneity.…”

Section: Introductionmentioning

confidence: 92%

“…[12][13][14][15]20,43 Additionally, LPBF has been applied to austenitic stainless steel powders mechanically alloyed with Y 2 O 3 . [16][17][18][19] While it has not been directly addressed in this study, it would be expected that the general sphericity of powders produced by gas atomization would be well suited for consistent bed formation during LPBF application of ODS powders compared with equivalent MA powders due to the resistance to flow caused by mechanical interlocking between irregular and satellite particles. 54,55,57 The internal structure of the powder particles was examined by TEM to determine the distribution of elements and to confirm the absence of Y-Ti dispersoids in the precursor powder.…”

Section: Powder Characterizationmentioning

confidence: 99%

“…Many studies using laser powder bed fusion (LPBF) AM have utilized ferritic or austenitic steels mechanically alloyed with Y 2 O 3 as AM feedstock. [10][11][12][13][14][15][16][17][18][19][20] Alternatively, low-energy ball milling and blending, [21][22][23] along with methods to deposit oxides onto powders in situ, have been reported as alternative feedstock techniques for fabrication by AM. [24][25][26][27][28] While some promising results have been reported, challenges related to heterogeneity and agglomeration of pre-existing Y 2 O 3 remain, and these approaches typically depend on MA processing, which can be a limiting factor to scalability.…”

Section: Introductionmentioning

confidence: 99%

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Laser Powder Bed Fusion of ODS 14YWT from Gas Atomization Reaction Synthesis Precursor Powders

Saptarshi

deJong

Rock

et al. 2022

JOM

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Laser powder bed fusion (LPBF) additive manufacturing (AM) is a promising route for the fabrication of oxide dispersion strengthened (ODS) steels. In this study, 14YWT ferritic steel powders were produced by gas atomization reaction synthesis (GARS). The rapid solidification resulted in the formation of stable, Y-containing intermetallic Y2Fe17 on the interior of the powder and a stable Cr-rich oxide surface. The GARS powders were consolidated with LPBF. Process parameter maps identified a stable process window resulting in a relative density of 99.8%. Transmission electron microscopy and high-energy x-ray diffraction demonstrated that during LPBF, the stable phases in the powder dissociated in the liquid melt pool and reacted to form a high density (1.7 × 1020/m3) of homogeneously distributed Ti2Y2O7 pyrochlore dispersoids ranging from 17 to 57 nm. The use of GARS powder bypasses the mechanical alloying step typically required to produce ODS feedstock. Preliminary mechanical tests demonstrated an ultimate tensile and yield strength of 474 MPa and 312 MPa, respectively.

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Section: Introductionmentioning

confidence: 92%

Section: Powder Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Laser Powder Bed Fusion of ODS 14YWT from Gas Atomization Reaction Synthesis Precursor Powders

Saptarshi

deJong

Rock

et al. 2022

JOM

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“…All these processes occur in the solid state, which has rather limited atomic mobility (diffusivity). More recently, laser-melting-based additive manufacturing (AM) technologies, such as laser powder bed fusion (LPBF) and laser direct energy deposition (LDED), have been demonstrated to be able to directly print ODS alloys with lightly mixed matrix powder (or wire) and oxide particles [14][15][16][17]. The oxide dispersion elements from the feedstock are dissolved in the melt pool and then precipitate out as oxide nano particles during rapid solidification.…”

Section: Introductionmentioning

confidence: 99%

“…The mechanical properties of ODS alloys are primarily controlled by the number density, composition and size of the oxide precipitates, which, in AM, vary with the process parameters, such as laser power and scanning speed [14][15][16][17][18][19][20][21]. Hence, it is important to establish a clear correlation between the oxide characteristics and the AM process parameters.…”

Section: Introductionmentioning

confidence: 99%

Atomic Diffusivities of Yttrium, Titanium and Oxygen Calculated by Ab Initio Molecular Dynamics in Molten 316L Oxide-Dispersion-Strengthened Steel Fabricated via Additive Manufacturing

Wang,

Yang,

Lawson

et al. 2024

Materials

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Oxide-dispersion-strengthened (ODS) steels have long been viewed as a prime solution for harsh environments. However, conventional manufacturing of ODS steels limits the final product geometry, is difficult to scale up to large components, and is expensive due to multiple highly involved, solid-state processing steps required. Additive manufacturing (AM) can directly incorporate dispersion elements (e.g., Y, Ti and O) during component fabrication, thus bypassing the need for an ODS steel supply chain, the scale-up challenges of powder processing routes, the buoyancy challenges associated with casting ODS steels, and the joining issues for net-shape component fabrication. In the AM process, the diffusion of the dispersion elements in the molten steel plays a key role in the precipitation of the oxide particles, thereby influencing the microstructure, thermal stability and high-temperature mechanical properties of the resulting ODS steels. In this work, the atomic diffusivities of Y, Ti, and O in molten 316L stainless steel (SS) as functions of temperature are determined by ab initio molecular dynamics simulations. The latest Vienna Ab initio Simulation Package (VASP) package that incorporates an on-the-fly machine learning force field for accelerated computation is used. At a constant temperature, the time-dependent coordinates of the target atoms in the molten 316L SS were analyzed in the form of mean square displacement in order to obtain diffusivity. The values of the diffusivity at multiple temperatures are then fitted to the Arrhenius form to determine the activation energy and the pre-exponential factor. Given the challenges in experimental measurement of atomic diffusivity at such high temperatures and correspondingly the lack of experimental data, this study provides important physical parameters for future modeling of the oxide precipitation kinetics during AM process.

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Additively Manufactured Stainless Steel Wind Tunnel Model Support Featuring Honeycomb Structures for Vibration Attenuation

Fu,

Peng,

Zhang

et al. 2024

Adv Eng Mater

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Wind tunnel model support (WTMS) is an indispensable component of wind tunnel testing. However, the presence of vibrations within the model‐support system can compromise the accuracy of data and give rise to significant safety hazards. In this study, an approach for vibration attenuation by incorporating honeycomb structures into the design of the WTMS is proposed. To this end, stainless steel WTMSs with integrated honeycomb structures are fabricated by selective laser melting (SLM). Results showed that stainless steels prepared under optimized SLM processing parameters exhibit high crystallinity and consist of single‐phase Fe–Cr–Ni alloy. The stainless steels exhibited robust mechanical properties, including a tensile strength of ≈1 GPa, an elongation of ≈8%, and a compressive strength of ≈1.4 GPa. These exceptional mechanical properties can be attributed to the formation of a cellular structure and tangled dislocations. The first‐order and the third‐order resonant response of WTMS honeycomb structures can be effectively reduced. The vibration reduction mechanism can be attributed to the occurrence of local resonance when the natural frequency of the internal periodic unit of the WTMS closely matched the vibration frequency of the model. The utilization of honeycomb structures holds significant potential for achieving vibration attenuation in WTMS.

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Thermal stability of additively manufactured austenitic 304L ODS alloy

Cited by 31 publications

References 49 publications

Laser Powder Bed Fusion of ODS 14YWT from Gas Atomization Reaction Synthesis Precursor Powders

Laser Powder Bed Fusion of ODS 14YWT from Gas Atomization Reaction Synthesis Precursor Powders

Atomic Diffusivities of Yttrium, Titanium and Oxygen Calculated by Ab Initio Molecular Dynamics in Molten 316L Oxide-Dispersion-Strengthened Steel Fabricated via Additive Manufacturing

Additively Manufactured Stainless Steel Wind Tunnel Model Support Featuring Honeycomb Structures for Vibration Attenuation

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