Layer-wise engineering of grain orientation (LEGO) in laser powder bed fusion of stainless steel 316L

Sofinowski, K.; Raman, Sudharshan; Wang, Xiaogang; Gaskey, Bernard; Seita, Matteo

doi:10.1016/j.addma.2020.101809

Cited by 52 publications

(40 citation statements)

References 31 publications

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“…By changing the scan strategy in a specimen, they demonstrated that texture and elastic anisotropy could be customized along the build-up direction by stacking different scanning regimes during the sequential build-up process at each position. Some related studies pertaining to not only L-PBF 39,64,65 but also EB-PBF 15,66 have also been reported. In case of EB-PBF, the focus is mainly of the mixture of <001> growth and random-oriented growth.…”

Section: Local Control Of Texture By Changing Scanning Strategy At Each Positionmentioning

confidence: 99%

“…Sofinowski et al reported locally customized L-PBF manufacturing for stainless steel 316L. 39 They successfully embedded cylinder-like controlled texture and changed the local texture pointwise with high spatial resolution. In addition, they reported a unique variation in texture by changing the scan direction by 1°in each layer.…”

Section: Local Control Of Texture By Changing Scanning Strategy At Each Positionmentioning

confidence: 99%

“…It is noteworthy that, in the study by Sofinowski et al, at every 1°rotation of the scan direction, it seems that the texture did not show a continuous change but a discrete variation. 39 This implies the appearance of a transient region in the texture when the scan strategy is changed during L-PBF. This was clearly elucidated in a recent study.…”

Section: Local Control Of Texture By Changing Scanning Strategy At Each Positionmentioning

confidence: 99%

See 2 more Smart Citations

Control of Anisotropic Crystallographic Texture in Powder Bed Fusion Additive Manufacturing of Metals and Ceramics—A Review

Hagihara

Nakano

2021

JOM

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Additive manufacturing (AM) enables the production of complex, net-shape geometries. Additionally, in AM of metal and ceramics, which has received less attention, the microstructure and texture of the product can be arbitrarily controlled by selecting appropriate process parameters, thereby enabling unprecedented superior properties. This paper discusses recent progress pertaining to texture evolution mechanisms and control methods, with an emphasis on selective laser melting. One of the unique characteristics of AM is that the texture can be varied as a function of position within the product by controlling the scan strategy. The transient behavior of the texture and the factor used to control it via the scan strategy are discussed. In addition, the texture evolution behavior of face- and body-centered cubic as well as noncubic materials is discussed. The importance of the crystallographic “multiplicity” of the preferential crystal growth direction is described to understand the evolution behavior of the texture in such materials.

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Section: Local Control Of Texture By Changing Scanning Strategy At Each Positionmentioning

confidence: 99%

Section: Local Control Of Texture By Changing Scanning Strategy At Each Positionmentioning

confidence: 99%

Section: Local Control Of Texture By Changing Scanning Strategy At Each Positionmentioning

confidence: 99%

See 1 more Smart Citation

Control of Anisotropic Crystallographic Texture in Powder Bed Fusion Additive Manufacturing of Metals and Ceramics—A Review

Hagihara

Nakano

2021

JOM

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“…(a) 316L stainless steel texture control with discrete changes in laser scan direction along the build height, reused from Ref. [11] under Creative Commons CC BY NC ND license, (b) pure Cr texture control with changes in energy density reused from Ref. [12] under Creative Commons CC-BY license, (c) nickel superalloy 718 texture control with laser power and laser power profile shape reused from Ref.…”

Section: List Of Figuresmentioning

confidence: 99%

“…The three examples in Fig. 1 show (a) manipulation of crystal texture in the X-plane with laser scan strategy [11], (b) crystallographic texture intensity decreasing with decreasing volumetric energy density [12], and (c) manipulation of crystal texture with laser power and power profile shape [13]. DebRoy et al [8] summarize the texture development process as competitive growth where easy growth crystal orientations aligned with the maximum heat flow outgrow slower, misaligned crystal orientations.…”

Section: Crystallographic Texturementioning

confidence: 99%

Understanding anisotropic tensile properties of laser powder bed fusion additive metals :

Weaver¹,

Rosenthal²

2021

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There are several physical reasons for anisotropic mechanical properties in additively manufactured metals. These include but are not limited to directionally dependent grain and phase morphology; crystallographic texture; directional porosity/defects; and heterogeneity associated with the melt pool, layer wise microstructure. All of these are prevalent in most additive manufacturing processes, and it is difficult to separate out the role that each play in the mechanical anisotropy. This review focuses on studies that have attempted to or reasonably isolate one or two of these sources rather than simply report on trends in mechanical properties. This is not an exhaustive review covering all additive process or mechanical properties; the main assessment is on laser powder bed fusion (LPBF) metals and tensile test results (modulus, yield strength, ultimate tensile strength (UTS), elongation, and fracture surface analysis). In summary, the primary sources of anisotropic tensile properties for LPBF alloys are crystallographic texture, anisotropic microstructure morphologies, lack of fusion defects, and the melt pool macrostructure. Within anisotropic microstructures, elongated grains appear to be secondary compared to the preferential distribution of phases and features (e.g., grain boundary alpha, precipitates, etc.). Anisotropic modulus and yield strength are primarily caused by crystallographic texture. This is supported by crystal plasticity simulations. Anisotropic elongation is primarily caused by anisotropic microstructure morphologies, lack of fusion defects, and melt pool macrostructure. The evidence to support this comes from fracture surfaces that follow these features. Melt pool macrostructure is the most challenging to experimentally isolate from the list of other sources of anisotropy. Strategies to characterize and manipulate crystallographic texture, porosity, grain and phase morphology, and melt pool macrostructures are required to better understand and control mechanical anisotropy in AM metals.

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Investigations of Microstructure and Mechanical Properties in Wire + Arc Additively Manufactured Niobium–Zirconium Alloy

et al. 2023

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Herein, the feasibility of the gas tungsten arc welding‐based wire + arc additive manufacturing process for fabricating thin wall structures of niobium‐1 wt% zirconium (NbZr1) alloy is investigated. Three different heat input conditions (low, medium, and high) have been selected for fabricating it. The microstructure is characterized by using optical microscopy, scanning electron microscopy, X‐ray diffraction, energy‐dispersive spectroscopy, and electron backscattered diffraction (EBSD). The microstructure shows the columnar dendritic structure elongated in the build direction. No cracks or porosity are observed in the structure. Average Vickers hardness for low, medium, and high heat input conditions are 146.6, 162.1, and 163.5 HV, respectively. There is an increasing trend of microhardness value along the deposition height, which can be attributed to the difference in secondary dendritic arm spacing and the formation of precipitates. The tensile strength of the specimen is comparable to the conventional and additively manufactured structures. EBSD analysis confirms that possible subgrains are responsible for good mechanical properties at room temperature. In the majority of the tensile samples, the failure mechanism has been identified as a ductile fracture. The mechanical characteristics fluctuate with locations in each of the thin walls, suggesting anisotropy in the deposits.

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Layer-wise engineering of grain orientation (LEGO) in laser powder bed fusion of stainless steel 316L

Cited by 52 publications

References 31 publications

Control of Anisotropic Crystallographic Texture in Powder Bed Fusion Additive Manufacturing of Metals and Ceramics—A Review

Control of Anisotropic Crystallographic Texture in Powder Bed Fusion Additive Manufacturing of Metals and Ceramics—A Review

Understanding anisotropic tensile properties of laser powder bed fusion additive metals :

Investigations of Microstructure and Mechanical Properties in Wire + Arc Additively Manufactured Niobium–Zirconium Alloy

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