Laser Powder-Bed Fusion as an Alloy Development Tool: Parameter Selection for In-Situ Alloying Using Elemental Powders

Aota, Leonardo Shoji; Bajaj, Priyanshu; Sandim, Hugo Ricardo Zschommler; Jägle, Eric Aimé

doi:10.3390/ma13183922

Cited by 34 publications

(12 citation statements)

References 53 publications

(68 reference statements)

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“…This is especially true if the melting point of the added elements is far above the melting point of the main alloying element. Aota et al [14] investigated in-situ alloy formation of 1.4307 (AISI 304L) from elemental Fe, Ni and Cr powder. They achieved a homogeneous element distribution for certain parameter combinations and concluded that the dwell time of the particles in the meltpool is crucial for achieving a complete dissolution of the particles.…”

Section: Introductionmentioning

confidence: 99%

Laser Powder Bed Fusion (PBF-LB/M) Process Strategies for In-Situ Alloy Formation with High-Melting Elements

Huber

Rasch

Schmidt

2021

Metals

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In-situ alloy formation by Laser Powder Bed Fusion (PBF-LB/M) from mixtures of easily available elemental powders is an appealing approach for developing and qualifying new alloys for laser based additive manufacturing of metals. However, especially when dealing with high-melting elements, like W, Ta, Mo, or Nb, it is difficult to achieve a homogeneous element distribution and a complete fusion of the powder particles. The aim of this work was to understand the effects of the PBF-LB/M process parameters (laser power, scan speed, laser spot diameter) and three different single- and double-exposure strategies on the fusion of high-melting W, Ta, Mo, and Nb particles in a Ti-matrix. For this purpose, 220 samples with 10 vol.% of the high-melting particle fraction were prepared and analyzed by optical light microscopy and automated image processing, as well as by scanning electron microscopy (SEM). The results are discussed in the context of current research on the process dynamics of PBF-LB/M. Based on that process strategies to support a complete fusion of high-melting particles during in-situ alloy formation are derived. It is shown that the number of unmolten particles can be at least decreased by a factor of ten compared to the most unfavorable parameter combination. For the lower melting elements, Nb and Mo, a complete fusion without any remaining particles visible in the microsections was achieved for certain parameter combinations. The results prove the feasibility of in-situ alloy formation with high-melting alloying elements, but they also demonstrate the necessity to adjust the PBF-LB/M process strategy to achieve a complete dissolution of the alloying elements.

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Section: Introductionmentioning

confidence: 99%

Laser Powder Bed Fusion (PBF-LB/M) Process Strategies for In-Situ Alloy Formation with High-Melting Elements

Huber

Rasch

Schmidt

2021

Metals

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“…To date, aluminium alloys have attracted wide interest thanks to their excellent strength-to-weight ratio, but their considerable solidification shrinkage, tendency to oxidation, high laser reflectivity and the poor flowability of their powders make these alloys challenging to process by PBF-LBM [6][7][8]. Considering the non-printability by PBF-LBM of some of the traditional high-strength Al alloys, the challenge of creating new tailored compositions is still ongoing [9,10].…”

Section: Introductionmentioning

confidence: 99%

Improvement in the PBF-LB/M processing of the Al-Si-Cu-Mg composition through the use of pre-alloyed powder

Martucci

Gobber

Aversa

et al. 2023

Mater. Res. Express

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Among the many additive manufacturing technologies for metals, Powder Bed Fusion-Laser Beam (PBF-LB\M) stands out for its capacity to produce complex-shaped functional parts. However, the PBF-LB\M materials portfolio is still limited and the research into new high-performance Al-based alloys is ongoing. The improved properties with the addition of 4 wt% Cu to the AlSi10Mg alloy have been previously investigated in the literature through the in-situ alloying approach in which the starting powders of Cu and AlSi10Mg are mechanically mixed and directly processed. However, inhomogeneities of alloying elements were found in samples produced with mixed AlSi10Mg+4Cu powders. To overcome this issue, the use of pre-alloyed AlSI10Cu4Mg powder obtained via gas atomisation process could be a powerful solution. With the aim of demonstrating the beneficial effects of pre-alloyed AlSi10Cu4Mg powders in laser-powder interaction, preliminary SEM investigations were conducted on cross-sectioned SSTs and bulk samples after optimising the process parameters. The microstructural investigations conducted on pre-alloyed AlSi10Cu4Mg samples revealed a higher homogeneity of alloying elements, a smaller cell size of the Al-Si-Cu network (0.5 vs 0.8 µm) and a slightly smaller mean diameter of equiaxial grains compared to the mixed AlSi10Mg+4Cu ones (6.01 vs 7.34 µm). Moreover, looking closer at the supersaturation level and the precipitation behaviour in pre-alloyed AlSi10Cu4Mg composition, a high solid solution level, a massive presence of Al2Cu in the cell network and only a few finely dispersed Al2Cu precipitates within the cells were found. Exploring the benefits of these microstructural features on mechanical properties, an increase in performance of about 18 % in micro-hardness tests and more than 10 % in tensile and compressive tests were found in the AlSi10Cu4Mg system with respect to the mixed AlSi10Mg+4Cu system. All the thorough investigations proved how using pre-alloyed powders is an important advantage in the PBF-LB/M production of complex Al-based systems.

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“…Mixing, blending and in-situ alloying for the production of adapted alloys have already been presented for LAM for different materials [9], such as high entropy alloys (HEAs) [8,[10][11][12], aluminum alloys [13][14][15][16][17][18], titanium [19][20][21][22] or stainless steels [23], but also for different LAM technologies [15,24,25]. Studies on wear-resistant Fe-based alloys are rarely found [9,26].…”

Section: Introductionmentioning

confidence: 99%

“…It is known that even some elemental powders, such as Ni [27], which have a similar melting temperature compared to Fe, can be dissolved during LAM. In contrast, higher melting elements, such as Cr or W, can hardly be dissolved in the melt pool [12,17,23,26]. The incomplete melting of raw material particles results in non-uniform chemical compositions as well as in high porosity [15,20,25,28].…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Processability and Influence on the Microstructure of Different Starting Powder Blends for Laser Powder Bed Fusion of a Fe3.5Si1.5C Alloy

Strauch

Uhlenwinkel

Steinbacher

et al. 2021

Metals

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This paper examines different blends of starting materials for alloy development in the laser powder bed fusion (LPBF) process. By using blends of individual elemental, ferroalloy and carbide powders instead of a pre-alloyed gas-atomized starting powder, elaborate gas-atomization processes for the production of individual starting powders with varying alloy compositions can be omitted. In this work the model alloy Fe3.5Si1.5C is produced by LPBF from different blends of pure elemental, binary and ternary powders. Three powder blends were processed. The base material for all powder blends is a commercial gas-atomized Fe powder. In the first blend this Fe powder is admixed with SiC, in the second with the ternary raw alloy FeSiC and in the third with FeSi and FeC. After characterizing the powder properties and performing LPBF parameter studies for each powder blend, the microstructures and the mechanical properties of the LPBF-manufactured samples were analyzed. Therefore, investigations were carried out by scanning electron microscopy, wave length dispersive x-ray spectroscopy and micro hardness testing. It was shown that the admixed SiC dissolves completely during LPBF. But the obtained microstructure consisting of bainite, martensite, ferrite and retained austenite is inhomogeneous. The use of the lower melting ferroalloys FeSi and FeC as well as the ternary ferroalloy FeSiC leads to an increased chemical homogeneity after LPBF-processing. However, the particle size of the used components plays a decisive role for the dissolution behavior in LPBF.

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Laser Powder-Bed Fusion as an Alloy Development Tool: Parameter Selection for In-Situ Alloying Using Elemental Powders

Cited by 34 publications

References 53 publications

Laser Powder Bed Fusion (PBF-LB/M) Process Strategies for In-Situ Alloy Formation with High-Melting Elements

Laser Powder Bed Fusion (PBF-LB/M) Process Strategies for In-Situ Alloy Formation with High-Melting Elements

Improvement in the PBF-LB/M processing of the Al-Si-Cu-Mg composition through the use of pre-alloyed powder

Comparison of the Processability and Influence on the Microstructure of Different Starting Powder Blends for Laser Powder Bed Fusion of a Fe3.5Si1.5C Alloy

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