Flow abilities of powders and granular materials evidenced from dynamical tap density measurement

Traina, Karl; Cloots, Rudi; Bontempi, Sébastien; Lumay, Geoffroy; Vandewalle, Nicolas; Boschini, Frèdéric

doi:10.1016/j.powtec.2012.11.039

Cited by 52 publications

(32 citation statements)

References 31 publications

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“…2. Three methods used for the measurement of the rheological properties of the powders: (A) heap shape analysis (GranuHeap instrument), (B) improved tapped density measurement method (GranuPaQ instrument), and (C) flow analysis in a rotating drum (GranuDrum instrument) [16].…”

Section: Heap Shape Methodmentioning

confidence: 99%

“…The Hausner ratios, the initial density and the final density are extracted from compaction curves [16]. The powder is placed in a metallic tube with a rigorous initialization process.…”

Section: Tapped Density Methodmentioning

confidence: 99%

“…The measurements have been performed with 25 ml of powder subjected to 500 taps [17]. The Hausner ratio is related to the compaction ratio and is calculated by the equation H r = ρ 0 /ρ 500 , where ρ 0 is the initial bulk density and ρ 500 the bulk density after 500 taps [16]. The protocol of the improved tapped density measurement method is described in more detail in [17].…”

Section: Tapped Density Methodmentioning

confidence: 99%

“…Unfortunately, the results obtained with this measurement method are limited and the interpretations are difficult [15]. During the last decade interesting techniques such as improved tapped density measurement [16], rotating drum method [17], shear cells [18] and powder rheometers [19] have been developed. However, the evolution of this field is still in its infancy.…”

Section: Introductionmentioning

confidence: 99%

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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: Heap Shape Methodmentioning

confidence: 99%

“…The Hausner ratios, the initial density and the final density are extracted from compaction curves [16]. The powder is placed in a metallic tube with a rigorous initialization process.…”

Section: Tapped Density Methodmentioning

confidence: 99%

Section: Tapped Density Methodmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…[6][7][8] By utilizing Eyring's rate process theory 9 and the free volume concept widely used in both liquids 10,11 and solids, 12 the inverse logarithmic and stretched exponential laws were derived pretty successfully. Nevertheless, many studies have shown that granular powders empirically obey the laws discovered in disordered thermal systems like glassy materials and colloidal dispersions.…”

Section: Introductionmentioning

confidence: 99%

Derivation of stretched exponential tap density equations of granular powders

Hao¹

2015

Soft Matter

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The tap density of granular powders was found to be better fitted with the stretched exponential law. In our previous work, the stretched exponential tap density equations were derived with the rate process theory and free volume concept, under the assumption that the particle packing rate during the tapping process obeys the stretched Arrhenius equation, which, however, has an empirical origin. In this article, the above assumption is eliminated and attempts are made to obtain the stretched exponential tap density equations from very fundamental bases. In a vertical tapping process, the probability of particles attaining certain energy states is assumed to obey the Boltzmann distribution and particles traveling from one site to another are assumed to follow a very common memoryless random exponential law. The stretched exponential tap density equations are thus derived and all parameters acquire clear physical meanings. The most important parameter, the stretched exponential, is demonstrated to correlate with the interparticle forces: a small value may indicate a strong adhesive or cohesive interaction. Therefore, the stretched exponential could be a better indicator for powder flowability correlated with particle interactions as well.

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New Methodology for Steady-State Friction Measurements of Granular Materials Under Pressure

Bek

González-Gutiérrez

Emri

2016

Conference Proceedings of the Society for Experimental Mechanics Series

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Flow abilities of powders and granular materials evidenced from dynamical tap density measurement

Cited by 52 publications

References 31 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

Derivation of stretched exponential tap density equations of granular powders

New Methodology for Steady-State Friction Measurements of Granular Materials Under Pressure

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