A Novel Process for Making Spherical Powders of High Nb Containing TiAl Alloys

2012 ◽  
Vol 520 ◽  
pp. 111-119 ◽  
Author(s):  
Xin Lu ◽  
L.P. Zhu ◽  
Xuan Hui Qu
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Argon Plasma ◽  
Average Diameter ◽  
Processing Parameters ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Distribution Uniformity ◽  
Jet Milling

A novel process was developed to make micro-fine spherical high Nb containing TiAl alloyed powders in quantity. Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y(at%) ingot prepared by vacuum induction melting was heat-treated for homogenization, and then machined with a crusher. The chippings were refined by fluidized bed jet milling, and subsequently spheroidized with radio frequency (RF) argon plasma. The effects of processing parameters on powder characteristics were studied. By fluidized bed jet milling, the particle size and distribution uniformity both decline with the rise of classifier frequency. Above 5800rpm, the number-average diameter is lower than 20μm with a bimodal particle size distribution. The powders consist of coarse plate-shaped particles and some finer flaky debris, and with the further rise of the frequency, the amount of debris gradually increases. The plasma-spheroidized powders are found to possess good sphericity and composition homogeneity with phase dominated by supersaturated α2-Ti3Al. The granulometric characteristics of the spherical powders strongly depend on those of the feed powders. For the jet milled powders below 5800rpm, due to the relatively lower size distribution uniformity, the fine particle fraction reduces after spheroidization, which causes an obvious improvement of distribution uniformity and the corresponding increase of number-average diameter

Particle size distribution control and related properties improvements of tungsten powders by fluidized bed jet milling

2017 ◽  
Vol 28 (6) ◽  
pp. 1603-1610 ◽  
Author(s):  
Rui Li ◽  
Mingli Qin ◽  
Chengcheng Liu ◽  
Zheng Chen ◽  
Xuanli Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Jet Milling ◽  
Tungsten Powders

Ultra-Fine Treatment of SiC Powder and Its Effect on Microstructure and Properties of SiC Ceramic

2007 ◽  
Vol 280-283 ◽  
pp. 1313-1316
Author(s):  
Xing Zhong Guo ◽  
Li Li ◽  
Li Hua Gao ◽  
Pei Xin Fu
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Specific Surface ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Sintering Temperature ◽  
Sic Ceramics ◽  
Sic Ceramic ◽  
Jet Milling

The ultra-fine treatment of industrial SiC powder was carried out by fluidized bed opposed jet milling (QLM-100K), and the influences of grinding parameters on the ultra-fine treatment were studied. A better grinding result is achieved through a higher crushing pressure and a higher sorter frequency and the ultra-fine treated SiC powder possesses a smaller particle size, a narrower particle-size distribution, a higher specific surface area and reduced agglomeration. The effects of ultra-fine treatment on the compaction behaviors, sintering behaviors, properties and microstructure of SiC ceramics were investigated. The compact with ultra-fine treated powder has a higher density and a lower sintering temperature. The densification and mechanical properties of the ceramics can be ameliorated obviously and the microstructure defects of the ceramics decrease.

scholarly journals RESEARCH OF THE EJECTING PROPERTIES OF A POLYFRACTION BULK MATERIAL FLOW

2018 ◽  
Vol 3 (3) ◽  
pp. 46-51
Author(s):  
Евгений Попов ◽  
Evgeniy Popov
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Material Flow ◽  
Bulk Material ◽  
Aerodynamic Resistance ◽  
Average Diameter ◽  
Resistance Coefficient ◽  
Free Falling ◽  
The Given

This work is aimed at confirming the adequacy of the probabilistic and statistical approach to determining the aerodynamic resistance coefficient of particles in a flow of the free falling polyfractional material, suggested by the author. The aerodynamic resistance coefficient of particles in a flow of falling material is defined by calculating the probability of finding particles out of air shadows of the neighboring particles. The laboratory experiment was performed on the offered experimental samples of bulk materials having different particle size distribution, but the identical average diameter of particles. The design of a laboratory experimental installation which allows determining the consumption of air, ejected by a polyfractional material flow, was described. The amount of the air, ejected with experimental samples, depends on their particle size distribution that confirms the insufficiency of describing the properties of bulk material only with the average diameter value. The given comparison of results of the analytical calculations with experimental data shows the reliability and adequacy of the calculated values.

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