In-situ alloying in powder bed fusion: The role of powder morphology

Knieps, Marius S.; Reynolds, William J.; Dejaune, Juliette; Clare, Adam T.; Evirgen, A.

doi:10.1016/j.msea.2021.140849

Cited by 28 publications

(11 citation statements)

References 23 publications

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“…[86,87] However, this can result in a multimodal particle size distribution (PSD) with variable particle morphologies and densities. [88] Moreover, blending might lead to inhomogeneity in the final built part's structure, since the melt pool in L-PBF is small and the ratio of elements might not be homogenous across the powder bed. This inhomogeneity can be caused by insufficient blending or segregation during transport.…”

Section: High-entropy Alloysmentioning

confidence: 99%

Emerging Functional Metals in Additive Manufacturing

Moghimian¹,

Poirié²,

Kroeger³

et al. 2023

Adv Eng Mater

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Section: High-entropy Alloysmentioning

confidence: 99%

Emerging Functional Metals in Additive Manufacturing

Moghimian¹,

Poirié²,

Kroeger³

et al. 2023

Adv Eng Mater

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“…[41][42][43] Recently developed high-entropy alloys obtained by this method have attracted attention. For example, Knieps et al [44] created a high-entropy superalloy composition through in situ alloying of two AM standard powders, IN718 and CoCr 75, via laser powder bed fusion. They proved that highly homogenous bulk parts could be printed by optimizing the raw powder morphology and particle size distribution.…”

Section: Introductionmentioning

confidence: 99%

High‐Entropy Alloy‐Induced Metallic Glass Transformation: Challenges Posed by in situ Alloying via Additive Manufacturing

et al. 2022

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In situ alloying and fabricating glassy structures through a layer‐by‐layer fashion approach are challenging but have high potential to develop novel‐graded materials. For the first time, this cost‐effective approach is applied to additive manufacturing (AM) of a Zr‐based bulk metallic glass (BMG) from high‐entropy alloys (HEAs). A newly developed composition of Zr40Al20Cu20Ti20 is fabricated through laser powder bed fusion (LPBF). Process parameters are optimized within a wide range of laser power (50–200 W) as well as scanning speed (50–800 mm s−1). In all printed samples, microscopic and compositional examinations reveal no glass formation, but very fine grains and CuTi and AlTi nanocrystals. Some glassy transitions at the interfaces may be encouraged to occur with proper melting and mixing. However, the main reason for not obtaining a glassy matrix is the substantial proportion of unmelted Zr raw powder throughout the structure as spherical particles. Consequently, glass formation can be hindered by a considerable amount of compositional deviation. During LPBF, in situ alloying poses significant challenges to developing BMGs. Hence, the various stages of the process, including raw material specifications, laser settings, and process parameters, should be investigated further.

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“…The in situ alloying by the LPBF still encounters such difficulties as the nonuniform distribution of elements and the insufficient melted elemental powders with high melting point and high porosity induced by the small size of melt pool. [ 14–16 ] The limited studies involved the in situ alloying of blends of two or three kinds of powders by additive manufacture, such as elemental Ti, Al, and V; [ 16,17 ] prealloyed FeCoNiCr and Mn or Al; [ 18–20 ] prealloyed FeCoNiCrMn and Ti; [ 21 ] elemental Ni and Ti, Nb or Sn; [ 14,22–24 ] AlSi10Mg and Cu; [ 25 ] Inconel 718 and CoCr75; [ 26 ] Inconel 625 and Ti6Al4V; [ 27 ] and elemental Ti and Nb. [ 28 ] The above studies mainly aimed to adjust the property of one well‐developed conventional alloy, such as eliminating the crack in as‐printed 7075 aluminum alloy by the addition of elemental Zr or Er powders [ 29,30 ] and triggering the transformation‐induced plasticity (TRIP) effect in the asprinted Ti6Al4V alloy by the addition of 316 L powders.…”

Section: Introductionmentioning

confidence: 99%

In situ Alloyed Medium Entropy Alloy Fabricated by Laser Powder Bed Fusion: Microstructure and Cryogenic Performance

Jia

et al. 2022

Adv Eng Mater

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An investigation is conducted into the feasibility to produce in situ alloyed medium entropy alloy containing four principal elements by laser powder bed fusion of the blended elemental powders. The effect of scan strategy, layer thickness, and laser power on in situ alloying is examined. It is revealed that the melting of Cr particles could be enhanced by increasing the remelting times of each building layer through the re‐scan strategy or reducing the powder layer thickness and by increasing the melting pool depth via large laser power. Besides, the combination of elemental uniformity and the low porosity in the printed alloy can be achieved. The accuracy of the nominal composition in the as‐printed sample could be ensured by the large remelting times combined with middle laser power, while an excessively large laser power could cause the loss of Cr element. Based on the high repetitive remelting process, the mechanism of pores elimination during in situ alloying is discussed. After the optimization, the as‐printed Fe60Co15Ni15Cr10 alloy fabricates with the re‐scan strategy or high laser power shows a tensile strength of ≈1140 MPa and an elongation of ≈0.39 under cryogenic loading. The as‐printed alloy overcomes the strength–ductility trade‐off at cryogenic temperature through the transformation‐induced plasticity.

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In-situ alloying in powder bed fusion: The role of powder morphology

Cited by 28 publications

References 23 publications

Emerging Functional Metals in Additive Manufacturing

Emerging Functional Metals in Additive Manufacturing

High‐Entropy Alloy‐Induced Metallic Glass Transformation: Challenges Posed by in situ Alloying via Additive Manufacturing

In situ Alloyed Medium Entropy Alloy Fabricated by Laser Powder Bed Fusion: Microstructure and Cryogenic Performance

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