Rationalization of solidification mechanism of Nd–Fe–B magnets during laser directed-energy deposition

Sridharan, Niyanth; Cakmak, Ercan; List, F.A.; Ucar, Huseyin; Constantinides, S.; Babu, S. S.; McCall, S.; Paranthaman, M.

doi:10.1007/s10853-018-2178-7

Cited by 23 publications

(20 citation statements)

References 23 publications

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“…(10), and for powder fed systems, a powder deposition density (PDD) [g mm −2 ] as in Eq. (11), where R powder is the powder feed rate in [g min −1 ].…”

Section: Thermal Aspectsmentioning

confidence: 99%

“…Therefore, the heat introduced to deposit each layer generates successive heat affected zones on previously deposited layers, in a process similar to multipass fusion welding [7][8][9][10]. As in welding, additive manufactured parts experience non-equilibrium solidification [11][12][13], due to fast cooling rates observed. The effect of multiple thermal cycles over these non-equilibrium structures may promote the formation of new phases and precipitates if the permanence time at a specific temperature for the solid-state transformation to occur is reached.…”

Section: Introductionmentioning

confidence: 99%

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Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Oliveira

Santos

Miranda

2020

Progress in Materials Science

467

134

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Additive manufacturing technologies based on melting and solidification have considerable similarities with fusion-based welding technologies, either by electric arc or high-power beams. However, several concepts are being introduced in additive manufacturing which have been extensively used in multipass arc welding with filler material. Therefore, clarification of fundamental definitions is important to establish a common background between welding and additive manufacturing research communities. This paper aims to review these concepts, highlighting the distinctive characteristics of fusion welding that can be embraced by additive manufacturing, namely the nature of rapid thermal cycles associated to small size and localized heat sources, the non-equilibrium nature of rapid solidification and its effects on: internal defects formation, phase transformations, residual stresses and distortions. Concerning process optimization, distinct criteria are proposed based on geometric, energetic and thermal considerations, allowing to determine an upper bound limit for the optimum hatch distance during additive manufacturing. Finally, a unified equation to compute the energy density is proposed. This equation enables to compare works performed with distinct equipment and experimental conditions, covering the major process parameters: power, travel speed, heat source dimension, hatch distance, deposited layer thickness and material grain size.

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“…(10), and for powder fed systems, a powder deposition density (PDD) [g mm −2 ] as in Eq. (11), where R powder is the powder feed rate in [g min −1 ].…”

Section: Thermal Aspectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Oliveira

Santos

Miranda

2020

Progress in Materials Science

467

134

View full text Add to dashboard Cite

show abstract

“…In contrast, additively-manufactured PMs can significantly reduce amounts of machining, enable complex geometries, and minimize material waste. Moreover, AM can control the grain texture to create isotropic or anisotropic properties [40], [41]. Thus, better magnetic performances (high remanence, coercivity, temperature stability, etc)can be achieved without heavy reliance on rare-earth materials like Dy, Tb, Pr, etc.…”

Section: D Printed Copper Components By Trumpf Section Iv Magnets Amentioning

confidence: 99%

Towards Fully Additively-Manufactured Permanent Magnet Synchronous Machines: Opportunities and Challenges

El-Refaie

2019

2019 IEEE International Electric Machines &Amp; Drives Conference (IEMDC)

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With the growing interest in electrification and as hybrid and pure electric powertrains are adopted in more applications, electrical machine design is facing challenges in terms of meeting very demanding performance metrics for example high specific power, harsh environments, etc. This provides clear motivation to explore the impact of advanced materials and manufacturing on the performance of electrical machines. This paper provides an overview of additive manufacturing (AM) approaches that can be used for constructing permanent magnet (PM) machines, with a specific focus on additivelymanufactured iron core, winding, insulation, PM as well as cooling systems. Since there has only been a few attempts so far to explore AM in electrical machines (especially when it comes to fully additivelymanufactured machines), the benefits and challenges of AM have not been comprehensively understood. In this regard, this paper offers a detailed comparison of multiple multi-material AM methods, showing not only the possibility of fully additively-manufactured PM machines but also the potential significant improvements in their mechanical, electromagnetic and thermal properties. The paper will provide a comprehensive discussion of opportunities and challenges of AM in the context of electrical machines.

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“…There are only a few studies focusing on fabrication of MQ powder by laser melting and electron beam melting . Commercially available MQP‐S powder is an atomized spherical nanocrystalline powder supplied by Magnequench Corporation.…”

Section: Amount Of Occurring Phases (ϕ η Nd‐rich Oxides) Grain Simentioning

confidence: 99%

“…A further challenge is related to the laser process itself. The high heating and cooling rates of the laser make the solidification sequence difficult to control . Recently, it has been demonstrated that fine‐tuning the laser parameters may result in stabilization of the intended Fe 14 Nd 2 B phase with reduced (but still present) iron segregation for high cooling rates and the MQP‐S powder used .…”

Section: Amount Of Occurring Phases (ϕ η Nd‐rich Oxides) Grain Simentioning

confidence: 99%

Refining the Microstructure of Fe‐Nd‐B by Selective Laser Melting

Goll

Vogelgsang

Pflanz

et al. 2018

Physica Rapid Research Ltrs

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Lab scale additive manufacturing of Fe‐Nd‐B based permanent magnet material (Fe75‐Nd18‐B7) has been performed. For fabrication a special inert gas process chamber for laser powder bed fusion has been used. This is required because Fe‐Nd‐B powders are extremely sensitive to oxidation. Selective laser melting (SLM) of the powders allows to realize very fine microstructures with a directed crystal growth and finely dispersed Nd‐rich phase. It is shown, that this fine and textured microstructure leads to large coercivity in sintered Fe‐Nd‐B magnets. A prototype has been realized by milling the SLM alloy and sintering.

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Rationalization of solidification mechanism of Nd–Fe–B magnets during laser directed-energy deposition

Cited by 23 publications

References 23 publications

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Towards Fully Additively-Manufactured Permanent Magnet Synchronous Machines: Opportunities and Challenges

Refining the Microstructure of Fe‐Nd‐B by Selective Laser Melting

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