Balling processes during selective laser treatment of powders

Толочко, Н. К.; Mozzharov, S. E.; Yadroitsev, Igor; Laoui, Tahar; Froyen, Ludo; Титов, В. И.; Ignatiev, Michail B.

doi:10.1108/13552540410526953

Cited by 249 publications

(102 citation statements)

References 1 publication

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“…When both the energy density and the scanning speed were very high, not only spatter particles but also some balling particles were observed on the surface. This phenomenon is the so-called "balling effect", which was reported elsewhere [31,32]. The size of balling particles reached hundreds of microns, which is much larger than that of spatter particles (ca.…”

Section: Characterization Of Zr-1mo Alloy Buildsmentioning

confidence: 96%

Fabrication and Characterization of a Low Magnetic Zr-1Mo Alloy by Powder Bed Fusion Using a Fiber Laser

Sun

Zhou

Kikuchi

et al. 2017

Metals

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Abstract:A low magnetic Zr-1Mo alloy was fabricated by a powder bed fusion (PBF) process using a fiber laser. The microstructure, surface morphology, and pore distribution of the as-built Zr-1Mo alloy were observed. Its magnetic susceptibility and Vickers hardness were evaluated by magnetic susceptibility balance and a microindentation tester, respectively. The as-built Zr-1Mo alloy mainly consisted of an α phase with an acicular structure. From the processing maps of the surface morphology and pore distribution, open pores on the top surface due to the lack of fusion corresponded to grid-like distributed pores, and large pores corresponded to balling particles on the top surface. The Vickers hardness was influenced by the oxygen and nitrogen contents rather than the porosity. The magnetic susceptibilities of the as-built Zr-1Mo alloy still were one-third those of Ti-6Al-4V and Ti-6Al-7Nb, thus PBF can be applicable to the fabrication process for the low magnetic Zr-1Mo alloy.

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Section: Characterization Of Zr-1mo Alloy Buildsmentioning

confidence: 96%

Fabrication and Characterization of a Low Magnetic Zr-1Mo Alloy by Powder Bed Fusion Using a Fiber Laser

Sun

Zhou

Kikuchi

et al. 2017

Metals

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“…The liquid metal splash is generated and ejected away from the melt pool surface. (d) Surface tension, wetting, de-wetting, and recoil pressure (mentioned by Das (2003) and Khairallah et al (2015)): Tolochko et al (2004) pointed out that balling effect caused by high viscosity and surface tension of the molten material tends to minimize surface area by forming liquid spheres which may result in very poor surface finish. The balling effect is partly responsible for the porosity defect of the final part.…”

Section: Introductionmentioning

confidence: 99%

Interfacial phenomena and characteristics between the deposited material and substrate in selective laser melting Inconel 625

Guo

Zhao³

2017

Journal of Materials Processing Technology

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“…Under laser heating, the material wants to group in a sphere. When too much energy is given, giants balls tend to form inside the part (balling effect) (Klocke and Wagner, 2003;Tolochko et al, 2004).…”

Section: Consolidation Processmentioning

confidence: 99%

Study of the inter‐particle necks in selective laser sintering

Jhabvala

Boillat

Glardon

2013

Rapid Prototyping Journal

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Purpose -Since pulsed lasers are mainly used in selective laser sintering (SLS) -contrarily to selective laser melting (SLM) -only the exterior of the powder particles is molten while their core stays solid. The purpose of this paper is to investigate the binding mechanism between two particles of titanium powder. Design/methodology/approach -A dedicated experimental setup is used to isolate the particles. They are then irradiated by the laser. SEM micrographs are taken at each step and image analysis is performed. The obtained results are compared with the predictions of a thermal model allowing for the incorporation of the latent heat of fusion and for a realistic surrounding. The absorbed laser intensity is modeled by means of the Mie theory. Findings -The growing of the interparticular necks and the volume of liquid formed for different repetition rates are measured and compared with numerical simulations. A good agreement is found. A new method to easily find the absorption coefficient of the laser into the grain and the heat exchange coefficient with the exterior is developed. Originality/value -This paper leads to a better understanding of the necking phenomena involved in the SLS consolidation process. An experimental set-up has been developed to observe and quantify the final state of a small amount of laser sintered grains. This process has been shown to be replicable and trustful. The thermal model leads to good predictions of the particle final sintering state.

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Balling processes during selective laser treatment of powders

Cited by 249 publications

References 1 publication

Fabrication and Characterization of a Low Magnetic Zr-1Mo Alloy by Powder Bed Fusion Using a Fiber Laser

Fabrication and Characterization of a Low Magnetic Zr-1Mo Alloy by Powder Bed Fusion Using a Fiber Laser

Interfacial phenomena and characteristics between the deposited material and substrate in selective laser melting Inconel 625

Study of the inter‐particle necks in selective laser sintering

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