Effect of Crystal Quality and Particle Size of HMX on the Creep Resistance for TATB/HMX Composites

2017 ◽  
Vol 42 (12) ◽  
pp. 1410-1417 ◽  
Author(s):  
Congmei Lin ◽  
Jiahui Liu ◽  
Guansong He ◽  
Zhijian Yang ◽  
Liping Pan ◽  
...  
Keyword(s):  
Particle Size ◽  
Creep Resistance ◽  
Crystal Quality

ANALYSIS OF WAVE CURVATURE EXPERIMENTS FOR MONOMODAL EXPLOSIVES WITH DIFFERENT CRYSTAL QUALITY AND PARTICLE SIZE CHARACTERISTICS

2008 ◽  
Author(s):  
G. T. Sutherland ◽  
E. R. Lemar ◽  
M. H. Marcus ◽  
Mark Elert ◽  
Michael D. Furnish ◽  
...  
Keyword(s):  
Particle Size ◽  
Crystal Quality ◽  
Wave Curvature

A Comparative Study on the Influence of Nb and Ti Additions to Different Processed Atomized Nial Powders.

1990 ◽  
Vol 213 ◽  
Author(s):  
Rainhard Laag ◽  
Wolfgang A. Kaysser ◽  
GÜnter Petzow
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Creep Resistance ◽  
Room Temperature ◽  
Average Particle Size ◽  
Full Density ◽  
Average Particle ◽  
Fracture Path ◽  
Density Distributions ◽  
Temperature Fracture

ABSTRACTPrealloyed powders of NiAl, NiAl-5Ti, NiAl-5Nb and NiAl-5Ti-5Nb (at.%) were gas atomized with an average particle size of 90 μm and cooling rates of > 104 K/s. The powders were attritor milled under Ar atmosphere reducing the average particle size to 1.5 μm. Sintering CIP compacts developed microstructure and density distributions, which allowed subsequent containerless HIPing to near full density (>98.5%) and a final grain size < 8 μm. Alloying of NiAl with 5at.% Nb or Ti increased its hardness, Young's modulus, toughness and creep resistance. The room temperature fracture path changed from primarily intergranular (NiAl) to primarily transgranular (Nb, Ti alloyed), increasing the Klc, values from 3.8 to 14.4 and 15.3 MPa√m, respectively. For comparison, HIPed materials from the as-atomized powders were also tested.

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

Analytical Electron Microscopy study of two vehicle-aged automotive exhaust catalysts having dissimilar activities

1989 ◽  
Vol 47 ◽  
pp. 272-273
Author(s):  
Sooho Kim ◽  
M. J. D’Aniello
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Noble Metal ◽  
Catalyst Deactivation ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Metal Particles ◽  
Automotive Exhaust ◽  
Exhaust Catalysts ◽  
Analytical Electron

Automotive catalysts generally lose-agtivity during vehicle operation due to several well-known deactivation mechanisms. To gain a more fundamental understanding of catalyst deactivation, the microscopic details of fresh and vehicle-aged commercial pelleted automotive exhaust catalysts containing Pt, Pd and Rh were studied by employing Analytical Electron Microscopy (AEM). Two different vehicle-aged samples containing similar poison levels but having different catalytic activities (denoted better and poorer) were selected for this study.The general microstructure of the supports and the noble metal particles of the two catalysts looks similar; the noble metal particles were generally found to be spherical and often faceted. However, the average noble metal particle size on the poorer catalyst (21 nm) was larger than that on the better catalyst (16 nm). These sizes represent a significant increase over that found on the fresh catalyst (8 nm). The activity of these catalysts decreases as the observed particle size increases.

Effect of particle size on erosion measurements and predictions in annular flow for an elbow

Wear ◽  
2020 ◽  
pp. 203579
Author(s):  
G. Haider ◽  
M. Othayq ◽  
J. Zhang ◽  
R.E. Vieira ◽  
S.A. Shirazi
Keyword(s):  
Particle Size ◽  
Annular Flow ◽  
Effect Of Particle Size
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