Effects of the Delivery Tube Diameter on the Qualities of Cu-9.7Sn-0.2P Alloy Powder Produced by Gas Atomization

2018 ◽  
Vol 913 ◽  
pp. 3-10
Author(s):  
Yu Wan Cheng ◽  
Zhi Yu Xiao ◽  
Hai Ping Zou
Keyword(s):  
Particle Size ◽  
Alloy Powder ◽  
Cost Effective ◽  
Tube Diameter ◽  
Gas Atomization ◽  
Delivery Tube ◽  
Powder Characteristics ◽  
Powder Particles ◽  
Particle Size And Shape ◽  
Dendritic Structures

Gas atomization is one of the most cost-effective methods for preparing spherical powders. The Cu-9.7Sn-0.2P alloy powder for 3D printing was prepared by a self-developed double nozzle gas atomization technique with different deliver tube diameters, and the particle size and shape of the powder were characterized. Results show that the powder particles are mostly nearly spherical, mixed with a few irregular powders. The average O. Bluntness of the powders are 60~70%, the average Outgrowths are lower than 18%. The deliver tube diameter affects the powder characteristics directly. The increase of the diameter increases the particle size of the powder and reduces the sphericity. At the same time, the adhesion of the satellite powder decreases, the flowability becomes better and the oxygen content drop. The surface and internal structure of the powder are mainly cellular and dendritic structures.

scholarly journals Determination of properties of non-spherical VT20 alloy powders for modelling packing density

2020 ◽  
Vol 96 (4) ◽  
pp. 56-63
Author(s):  
Z.A. Duriagina ◽  
◽  
I.A. Lemishka ◽  
V.V. Kulyk ◽  
H.A. Hrydova ◽  
...  
Keyword(s):  
Particle Size ◽  
Titanium Alloy ◽  
Packing Density ◽  
Alloy Powder ◽  
Fractional Composition ◽  
Spherical Particles ◽  
Vt20 Alloy ◽  
Powder Particles ◽  
Vt20 Titanium Alloy

The study of unfavorable titanium alloy powders of VT20 grades was carried out and the methods of computer analysis were applied to determine the parameters of their optimal packaging. Metallographic studies were performed on a scanning electron microscope EVO-40XVP, and elemental analysis was performed using an energy dispersion spectrometer OXFORD INCA Energy 350. Determination of particle size distribution of powders was performed using image analysis software ImageJ. The surface morphology of non-spherical particles of VT20 alloy powder was studied for three different fractions: 100 ... 160 μm, 160 ... 200 μm and 200 ... 250 μm. It is shown that the powder particles are characterized by a nonspherical shape and a small difference in size. There is a tendency according to which when the particle size of the powder of the investigated alloy decreases, their shape approaches spherical. According to the results of particle size analysis, it was found that the usual sieve analysis does not allow to fully assess the distribution of powder by fractions. It was found that for the fraction 200 ... 250 μm the dominant particles are with an average diameter of 226 μm, for the fraction 160 ... 200 μm - 177 μm and for the fraction 100 ... 160 μm - 114 μm, respectively. Thus, for the fraction of titanium powder of the BT20 brand 200 ... 250 the polydispersity is 6.4%, for the fraction 160 ... 200 - 8.3%, and for the fraction 100 ... 160 - 9.1%. It is established that the fluidity of titanium alloy powders of the BT20 brand is: for the fraction 200 ... 250 μm - 62.35 s, for the fraction 160 ... 200 μm - 65.44 s, and for the fraction 100 ... 160 - 68, 73 s. That is, the highest value of fluidity is characterized by the powder with the largest particle size. Simulation of the pre-defined volume filling was performed using the "Spheres test" program. The average radii of particles of VT20 titanium alloy powder particles and the probability of the sizes of each of fractions of powder which is necessary at filling of the set volume was calculatedthe possibility of their precipitation have been established. Based on the obtained results, the packing density of VT20 titanium alloy powders was calculated depending on their fractional composition. It is confirmed that as the particle size of the powder decreases, their packing density increases. The surface morphology of non-spherical particles of VT20 alloy powder of different fractional composition and their particle size characteristics were studied. It is shown that with decreasing fractional composition of powder fractions, their homogeneity and bulk density increase. It was found that finer fractions are characterized by poorer fluidity. The simulation results determine the optimal fractional composition of the powder to fill the pre-specified volume. It is shown that as the size of the test particles decreases, their packing density increases. Keywords: additive production, titanium, microstructure, particle size distribution, bulk density, fluidity, packing density modelingmodelling.

scholarly journals Polyamide 12 Materials Study of Morpho-Structural Changes during Laser Sintering of 3D Printing

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 810 ◽  
Author(s):  
Gražyna Simha Martynková ◽  
Aleš Slíva ◽  
Gabriela Kratošová ◽  
Karla Čech Barabaszová ◽  
Soňa Študentová ◽  
...  
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Structural Changes ◽  
Point Of View ◽  
Scale Production ◽  
Polyamide 12 ◽  
Powder Particles ◽  
Particle Size And Shape

The polyamide (PA)-12 material used for additive manufacturing was studied in aspects of morphology and their structural properties for basic stages received during 3D laser printing. Samples were real, big-scale production powders. The structure of polymer was evaluated from the crystallinity point of view using XRD, FTIR, and DSC methods and from the surface properties using specific surface evaluation and porosity. Scanning electron microscopy was used to observe morphology of the surface and evaluate the particle size and shape via image analysis. Results were confronted with laser diffraction particles size measurement along with an evaluation of the specific surface area. Fresh PA12 powder was found as inhomogeneous in particle size of material with defective particles, relatively high specific surface, high lamellar crystallite size, and low crystallinity. The scrap PA12 crystallinity was about 2% higher than values for fresh PA12 powder. Particles had a very low, below 1 m2/g, specific surface area; particles sintered as twin particles and often in polyhedral shapes.

scholarly journals INFLUENCE OF POWDER CHARACTERISTICS ON THE SPREADABILITY OF PRE-ALLOYED TUNGSTEN- CARBIDE COBALT

2021 ◽  
Vol 32 (3) ◽  
pp. 284-289
Author(s):  
Preyin Govender ◽  
Deborah Clare Blaine ◽  
Natasha Sacks
Keyword(s):  
Particle Size ◽  
Flow Rate ◽  
Base Plate ◽  
Angle Of Repose ◽  
Critical Parameters ◽  
Powder Bed ◽  
Powder Characteristics ◽  
Particle Size And Shape ◽  
Spray Dried ◽  
Selection Of

With rising interest in additive manufacturing (AM) techniques, there is an increased focus on research that evaluates critical parameters that guide the selection of powders that are suitable for AM. One such parameter is a powder’s spreadability, described by metrics such as powder bed density and percentage coverage. This study focused on three spray-dried WC-Co powders (two 12 wt% and one 17 wt% Co) and evaluated the influence of typical powder characteristics, such as particle size and shape, apparent density, and flow rate, on their spreadability. It was found that particle size distribution influenced the powder spreadability. Larger particles hindered the even spreading of powder over the base plate, resulting in low powder bed density and percentage coverage. This also correlated with the powders’ apparent densities. The flow rate and angle of repose gave an indication of how cohesive the powders are. The more cohesive a powder, the poorer the spreadability, resulting in a lower powder bed density and percentage coverage.

Shock consolidation of Ni-Ti alloy powder

1986 ◽  
Vol 44 ◽  
pp. 430-431
Author(s):  
Naresh N. Thadhani ◽  
Thad Vreeland ◽  
Thomas J. Ahrens
Keyword(s):  
Alloy Powder ◽  
Amorphous Material ◽  
Ti Alloy ◽  
Two Phase ◽  
Near Surface ◽  
Optical Micrograph ◽  
Shock Compaction ◽  
Powder Particles ◽  
Ti Powder ◽  
Rapidly Solidified

A spherically-shaped, microcrystalline Ni-Ti alloy powder having fairly nonhomogeneous particle size distribution and chemical composition was consolidated with shock input energy of 316 kJ/kg. In the process of consolidation, shock energy is preferentially input at particle surfaces, resulting in melting of near-surface material and interparticle welding. The Ni-Ti powder particles were 2-60 μm in diameter (Fig. 1). About 30-40% of the powder particles were Ni-65wt% and balance were Ni-45wt%Ti (estimated by EMPA).Upon shock compaction, the two phase Ni-Ti powder particles were bonded together by the interparticle melt which rapidly solidified, usually to amorphous material. Fig. 2 is an optical micrograph (in plane of shock) of the consolidated Ni-Ti alloy powder, showing the particles with different etching contrast.

scholarly journals Impact of Coseismic Frictional Melting on Particle Size, Shape Distribution and Chemistry of Experimentally-Generated Pseudotachylite

2020 ◽  
Vol 8 ◽  
Author(s):  
Leny Montheil ◽  
Virginia G. Toy ◽  
James M. Scott ◽  
Thomas M. Mitchell ◽  
David P. Dobson
Keyword(s):  
Particle Size ◽  
Host Rock ◽  
Fractal Dimensions ◽  
Rock Composition ◽  
Slip Rates ◽  
Shape Distribution ◽  
Frictional Behavior ◽  
Particle Size And Shape ◽  
Frictional Melting ◽  
Glass Compositions

In natural friction melts, or pseudotachylites, clast textures and glass compositions can influence the frictional behavior of faults hosting pseudotachylites, and are, in turn, sensitive to the processes involved in pseudotachylite formation. Quantification of these parameters in situations where the host rock composition and formation conditions are well-constrained, such as analogue experiments, may yield calibrations that can be employed in analysis of natural pseudotachylites. In this paper, we experimentally-generated pseudotachylites in granitoid rocks (tonalite and Westerly granite) at Pconf = 40 MPa and slip rates of ∼0.1 m s−1, comparable to the conditions under which natural pseudotachylite is known to form in Earth’s upper crust. We find variations in both clast textures and glass compositions that reflect formation processes, and probably influence the frictional behavior of similar natural faults hosting pseudotachylite. Quantification of particle size and shape distribution with a semi-automatic image analysis method, combined with analysis of glass and host-rock composition of these experimentally generated pseudotachylites, reveals that the textures of pseudotachylite material evolved by combinations of 1) comminution, 2) heterogeneous frictional flash melting, and 3) homogeneous (diffusive) clast melting and/or marginal decrepitation. Fractal dimensions of pseudotachylite-hosted clasts (D ∼ 3) that are greater than those of marginal fragmented host rock particles (gouge, D ∼ 2.4), reflect an increase of the intensity of comminution by slip localisation during a pre-melting phase. Chemical analyses demonstrate that these pseudotachylite glasses were generated by frictional flash melting, where host rock phases melt individually. Biotite is the least resistant to melting, feldspar intermediate, and quartz is the most resistant. The peudotachylite glass generated in these experiments has an alkaline composition, is depleted in SiO2 compared to the bulk host-rock, and shows heterogeneous compositions in a single sample related to proximity to host-rock minerals. The percentage contributions of host rock phases to the melt, calculated by a mixing model, shows that glass compositions are dominated by plagioclase and biotite. Within the melt, margins of clasts were dissolved uniformly by diffusion and/or affected by marginal decrepitation, resulting in convex and round shapes with convexities averaging ∼0.8 and circularities averaging ∼0.65.

Effect of Composition on the Morphology and Hardness of Nanostructured Cu Based Composite and Alloy Powders/Granules Produced by High Energy Mechanical Milling

2007 ◽  
Vol 29-30 ◽  
pp. 143-146 ◽  
Author(s):  
Aamir Mukhtar ◽  
De Liang Zhang ◽  
C. Kong ◽  
P. R. Munroe
Keyword(s):  
Grain Size ◽  
Mechanical Milling ◽  
Alloy Powder ◽  
High Energy ◽  
Al2o3 Nanoparticles ◽  
X Ray ◽  
Fine Powders ◽  
Average Grain Size ◽  
Powder Particles

Cu-(2.5 or 5.0vol.%)Al2O3 nanocomposite balls and granules and Cu-(2.5vol.% or 5.0vol.%)Pb alloy powder were prepared by high energy mechanical milling (HEMM) of mixtures of Cu and either Al2O3 or Pb powders. It was observed that with the increase of the content of Al2O3 nanoparticles from 2.5vol.% to 5vol.% in the powder mixture, the product of HEMM changed from hollow balls into granules and the average grain size and microhardness changed from approximately 130nm and 185HV to 100nm and 224HV, respectively. On the other hand, HEMM of Cu–(2.5 or 5.0vol.%) Pb powder mixtures under the same milling conditions failed to consolidate the powder in-situ. Instead, it led to formation of nanostructured fine powders with an average grain size of less than 50nm. Energy dispersive X-ray mapping showed homogenous distribution of Pb in the powder particles in Cu–5vol.%Pb alloy powder produced after 12 hours of milling. With the increase of the Pb content from 2.5 to 5.0 vol.%, the average microhardness of the Cu-Pb alloy powder particles increases from 270 to 285 HV. The mechanisms of the effects are briefly discussed.

Advanced gas atomization processing for Ti and Ti alloy powder manufacturing

JOM ◽  
2010 ◽  
Vol 62 (5) ◽  
pp. 35-41 ◽  
Author(s):  
A. J. Heidloff ◽  
J. R. Rieken ◽  
I. E. Anderson ◽  
D. Byrd ◽  
J. Sears ◽  
...  
Keyword(s):  
Alloy Powder ◽  
Gas Atomization ◽  
Ti Alloy ◽  
Powder Manufacturing

INFLUENCE OF METAL POWDER PRODUCTION METHOD ON MICROSTRUCTURE AND FLUIDITY OF MAGNETICALLY ALLOY GRANULATE

2021 ◽  
Vol 2021 (9) ◽  
pp. 3-7
Author(s):  
Dmitriy Kostin ◽  
Aleksandr Amosov ◽  
Anatoliy Samboruk ◽  
Bogdan Chernyshev ◽  
Anton Kamynin
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Comparative Studies ◽  
Particle Morphology ◽  
Production Method ◽  
Magnetic Alloy ◽  
Gas Atomization ◽  
Metal Powders ◽  
Hard Magnetic Alloy

A comparison is made of the characteristics of metal powders of a hard magnetic alloy produced by centrifugal spraying and gas atomization. Comparative studies of particle morphology and particle size distribution of powders are presented in order to determine them.

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