Heat exchange between metal particles and gas in the atomization process

Nichiporenko, O. S.; Naida, Yu. I.

doi:10.1007/bf00774694

Cited by 44 publications

(5 citation statements)

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“…For instance, a decrease in the velocity of argon gas used to break up a melt stream into droplets during the gas atomization process could result in droplet spheroidization time (t sph ) longer than that of solidification (t sol ). If t sph N t sol solidifying droplets tend to form non-spherical particles [24].…”

Section: Powder Synthesis and Characterizationmentioning

confidence: 99%

Rheological behavior of β-Ti and NiTi powders produced by atomization for SLM production of open porous orthopedic implants

et al. 2015

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The growing interest for Selective Laser Melting (SLM) in orthopedic implant manufacturing is accompanied by the introduction of novel Ti alloys, in particular β-Ti for their excellent corrosion resistance as well as favorable combination of high mechanical strength, fatigue resistance and relatively low elastic modulus. As part of the SLM process for producing quality β-Ti parts powder flowability is essential to achieve uniform thickness of powder layers. In this work the flowability of different gas atomized β-Ti, including NiTi, powders has been studied. Their rheological properties were compared to those of commercially available plasma-atomized Ti-6Al-4V powder using a newly developed semi-automatic experimental set-up. Not only the particle size, shape and size distribution of the powders display a large influence on the powder flowability but also particle surface properties such as roughness, chemical composition and the presence of liquid on the surface of the particles. It was found that plasma or gas atomization production techniques for SLM powder have a considerable effect on the particle topography. Among the powders studied regarding SLM applicability only rheological properties of the fine size fraction (25-45 μm) of Ti-45Nb didn't conform to SLM processing requirements. To improve flowability of the Ti-45Nb powder it was annealed both in air and argon atmosphere at 600°C during 1 h, resulting in an improved rheological behavior suitable for SLM processing.

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Section: Powder Synthesis and Characterizationmentioning

confidence: 99%

Rheological behavior of β-Ti and NiTi powders produced by atomization for SLM production of open porous orthopedic implants

et al. 2015

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“…The solidification and spheroidization time of a droplet in a gas stream determine the shape of a powder. When the solidification time is less than the spheroidization time required, the powder is spherical, otherwise, the non-spherical powder is obtained [25]. The low-temperature argon is used as atomizing gas by EIGA.…”

Section: Sphericitymentioning

confidence: 99%

Characterization of Ti6Al4V powders produced by different methods for selective electron beam melting

Liu

Huang

Gao

et al. 2019

J min metall B Metall

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Three different types of Ti6Al4V powders produced by electrode induction melting gas atomization (EIGA), plasma rotating electrode process (PREP), and plasma atomization (PA) were compared from these aspects: particle size distribution, particle shape, and microstructure. Theywere characterized by particle size and shape analyzer, scanning electron microscope, and X-ray diffraction. The results show some benefits of using PA Ti6Al4V powder in selective electron beam melting. The particle size distribution of these Ti6Al4V powders were bimodal, and the PA Ti6Al4V powder had the narrowest particle size span. The roundness and elongation, the bluntness index of the most analyzed Ti6Al4V powders were greater than 80%. There were 52%, 81%, and 93% Ti6Al4V powders without satellite, respectively. These particle shape results indicate that EIGA, PRER, and PA Ti6Al4V powders have good sphericity and low content of satellites. The flowability of PA (20.55 s/50 g) is better than that of EIGA (24.80 s/50 g) and PREP (25.76 s/50 g). The microstructure of Ti6Al4V powders was composed of martensite α′.

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“…The time it takes to deform and disrupt a droplet is described by the characteristic break-up time which is a result of Rayleigh-Taylor or Kelvin-Helmholtz (Levich, 1962;Bradley, 1973) instabilities. The spheroidization time for a droplet (Nichiporenko and Naida, 1968;Markus and Fritsching, 2006) after break-up is comparably small and hence the new droplets can be assumed to be spherical immediately after break-up. Depending on the initial Weber number, the droplets will deform and eventually break up in different sized fragments.…”

Section: Droplet Modelingmentioning

confidence: 99%

Numerical and experimental analysis of vertical spray control patternators

Sarghini¹,

Pergher²

2013

J Agricult Engineer

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The experimental vertical spray control walls have the purpose of picking up the liquid delivered by trained sprayer for providing the liquid distribution profile in height. Theoretically this should correspond to the ideal profile, which consists in a uniform distribution on the vegetation. If the profile is different from the ideal, a parameter setup is required on the sprayer. Nonetheless, some problems are hidden in the aforementioned statements: i) no wall measures exactly the distribution profile (i.e. the flow through the sections in the vertical plane, parallel to the direction of advancement of the sprayer). Compared to real profile, sensitive errors are introduced: the evaporation of the drops, the deviation of the air flows caused by the sensors panel themselves; by the possibility that the drops bounce on the wall panels, also due to the current of air that can push the liquid veil laterally or upwards, Moreover, everything varies depending on the geometry of the sensors, air velocity, air humidity; ii) no one knows what exactly is the optimal distribution profile. It is often considered as optimal a profile that reflects the amount of leaf area subtended by each section absorber: however, it is evident that the path of the droplets changes according to the sprayer typology (eg. radial-flow or horizontal flows). In this work a combined numerical-experimental approach is adopted, in order to assess some of the aforementioned issues: numerical data obtained by using computational fluid dynamics models are compared and validated with experimental data, in order to assess the reliability of numerical simulations in configurations which are difficult to analyze using an experimental setup.

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Heat exchange between metal particles and gas in the atomization process

Cited by 44 publications

References 0 publications

Rheological behavior of β-Ti and NiTi powders produced by atomization for SLM production of open porous orthopedic implants

Rheological behavior of β-Ti and NiTi powders produced by atomization for SLM production of open porous orthopedic implants

Characterization of Ti6Al4V powders produced by different methods for selective electron beam melting

Numerical and experimental analysis of vertical spray control patternators

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