Molybdenum and tungsten manufactured by selective laser melting: Analysis of defect structure and solidification mechanisms

Braun, J.; Kaserer, Lukas; Stajkovic, J.; Leitz, Karl-Heinz; Tabernig, B.; Singer, Péter; Leibenguth, P.; Gspan, Christian; Kestler, H.; Leichtfried, Gerhard

doi:10.1016/j.ijrmhm.2019.104999

Cited by 129 publications

(50 citation statements)

References 19 publications

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“…The columnar grains grew epitaxially on the previously solidified track. Simultaneously, the oxygen solute atoms were expelled into the GBs and formed oxides . Such columnar crystals lead to extremely fragile grain bonding for brittle tungsten, which will exert an adverse effect on the mechanical properties.…”

Section: Resultsmentioning

confidence: 99%

“…The GBs between columnar grains are high angle grain boundaries with significant orientation difference . In the plastic deformation, the deformation of grains is not arbitrary, and such high angle grain boundaries need to coordinate the deformation between adjacent grains, so they often become the crack sources under stress.…”

Section: Resultsmentioning

confidence: 99%

“…Yet, this covalent bonding has strong directionality, which does not allow the relative position between the atoms to be changed, so that the material does not have plasticity. In addition, the interstitial impurities have a significant effect on the brittleness, which is extremely susceptible to oxygen, and a trace amount of oxygen causes the DBTT rise sharply . Accordingly, tungsten is arduous to the machine.…”

Section: Introductionmentioning

confidence: 99%

“…fabricated pure tungsten samples with a relative density of 98.5% using SLM. Recent literature also revealed that nearly full‐dense tungsten could be prepared by SLM. In view of the characteristics of SLM, however, the manufacture of high melting point tungsten still faces some technical challenges.…”

Section: Introductionmentioning

confidence: 99%

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Selective Laser Melting and Remelting of Pure Tungsten

et al. 2020

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The processing of pure tungsten encounters a substantial challenge due to its high melting point and intrinsic brittleness. Selective laser melting (SLM) technique is gaining popularity and offers an excellent processing approach for refractory metals. Herein, dense pure tungsten specimens are produced by optimizing SLM processing parameters. The mechanical property of the SLM‐produced tungsten with an ultimate compressive strength of about 1200 MPa, which is obviously superior to that reported in other literature, is achieved. The increased laser energy input is instrumental in raising density and surface roughness of tungsten specimens. Interestingly, additional remelting of processed layers during SLM improves the surface quality and the microstructure and achieves the highest relative density (98.4% ± 0.5%). After laser remelting, the surface roughness is reduced by 28% and a large number of fine grains are obtained. The flow of fluids caused by remelting plays a decisive role in the formation of fine grains and the defect level. Therefore, these findings offer a new insight into SLM of pure tungsten.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Selective Laser Melting and Remelting of Pure Tungsten

et al. 2020

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“…Generally, grain boundary (GB) segregation of interstitial elements (e.g. O, N) could weaken the cohesion strength of GB and thus lead to a high DBTT [14,16]. Therefore, low temperature ductility of W could be improved by introducing trace amounts of active second-phase ZrC particles, which was believed to be one of the most promising strengthening phases for W due to its higher melting point (3540 °C) and good compatibility with W [3].…”

Section: Introductionmentioning

confidence: 99%

Selective laser melting high-performance ZrC-reinforced tungsten composites with tailored microstructure and suppressed cracking susceptibility

et al. 2021

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Selective laser melting (SLM) tungsten (W) constantly suffered from severe cracking phenomenon due to the high melting temperature and low intrinsic ductility of W material. To address this significant issue, active ZrC nanoparticles were introduced into the W matrix to form ZrC/W composites in situ by SLM to enhance the intrinsic toughness of W in this study. It mainly focused on the effect of ZrC nanoparticle on the microstructure and cracking behavior of SLM W. Compared to SLM W, SLM ZrC/W composites showed finer equiaxed grains rather than columnar grains, because the ZrC nanoparticles provided many heterogeneous nucleation sites. Furthermore, ZrC nanoparticles could react with oxygen impurity at the grain boundaries (GBs), and then form stable ZrO 2 and ZrW 2 O 8 to purify and improve the cohesion strength of GBs. The columnar to equiaxed transition (CET) of grains and purified GBs played an important role in inhibiting the formation and propagation of the cracks in SLM W. Therefore, SLM ZrC/W composites exhibited lower crack density and higher mechanical properties compared to SLM W. This study provides a novel approach for suppressing the cracking susceptibility of SLM W.

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Alloy Design for Metal Additive Manufacturing

Dovgyy

Pham

2023

Additive Manufacturing Technology

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Molybdenum and tungsten manufactured by selective laser melting: Analysis of defect structure and solidification mechanisms

Cited by 129 publications

References 19 publications

Selective Laser Melting and Remelting of Pure Tungsten

Selective Laser Melting and Remelting of Pure Tungsten

Selective laser melting high-performance ZrC-reinforced tungsten composites with tailored microstructure and suppressed cracking susceptibility

Alloy Design for Metal Additive Manufacturing

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