Nanocrystallite Characterization of the MMC 316L-0.3%wtY2O3-3%wtTaC by Rietveld Refinement Method

2010 ◽  
Vol 636-637 ◽  
pp. 177-183
Author(s):  
W.M. de Carvalho ◽  
Uilame Umbelino Gomes ◽  
Carlson P. de Souza ◽  
M. Furukava
Keyword(s):  
Crystallite Size ◽  
Milled Powder ◽  
High Energy ◽  
Milling Process ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Nanocrystallite Size ◽  
Refinement Method ◽  
316L Steel

The nanocrystallites in a metal matrix composite (MMC) have wide importance in the sintering area. The nanocrystallites have been related with properties such as hardness and density of 316L steel matrixes. The Y2O3 and TaC dispersion in steel crystalline structures affects these properties and the sintering process. This study analyze: the 316L steel, Y2O3 and TaC crystallite size; TaC and Y2O3 dispersion in milled powder composite; MMC nanocrystallite size and micro-strain during milling process of 316L-(CFC) steel and the effects of dispersion in sintered MMC. The alloy was submitted to high energy milling. MMC was characterized by scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The diffraction was analyzed by Rietveld’s refinement method, DBWS 9807 program, and crystallite size and micro-strain were performed using Scherrer’s equation and Williamson-Hall’s method.

High Velocity Nano Alumina Wet Milling in Zirconia and Corundum Mills

2011 ◽  
Vol 83 ◽  
pp. 255-260 ◽  
Author(s):  
Yusoff M.S. Meor ◽  
Paulus Wilfred ◽  
Muslimin Masliana
Keyword(s):  
Crystallite Size ◽  
Lattice Strain ◽  
High Energy ◽  
Milling Process ◽  
Alumina Powder ◽  
Wet Milling ◽  
Optimum Conditions ◽  
X Ray Diffraction ◽  
Nano Alumina ◽  
Tangent Method

The paper presents a study on the effect of high energy milling to the crystallite size and lattice strain of α-alumina in zirconia and corundum mills. A Fritsch Pervesette 7 which has a maximum milling speed of 1100 rpm was used for this comparison. Milled samples were analyzed using the X-Ray Diffraction (XRD) technique to calculate for the crystallite size using the Scherrer method while lattice strain was determined by the Tangent method. Scanning electron microscope (SEM) was also used to determine changes in the morphology of the alumina powder sample after the milling process. Zirconia was found to be the better abrasive material and the optimum conditions used to obtain the smallest crystallite size of 51.2 nm are milling speed and time of 1100 rpm and 180 minutes respectively.

Structure and microstructure characterization of the mixed sesquioxides (Gd1−xYbx)2O3and (Gd1−xHox)2O3prepared by sol–gel process

2005 ◽  
Vol 38 (2) ◽  
pp. 306-310 ◽  
Author(s):  
Z. K. Heiba ◽  
L. Arda ◽  
Y. S. Hascicek
Keyword(s):  
Crystallite Size ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
Refinement Method ◽  
Cationic Distribution ◽  
Sol Gel Process ◽  
Structure And Microstructure

Polycrystalline samples of (Gd1−xYbx)2O3and (Gd1−xHox)2O3(0.0 ≤x≤ 1.0) were synthesized by a sol–gel process. X-ray diffraction data were collected and crystal structure and microstructure analyses were performed using the Rietveld refinement method. All samples were found to have the same crystal system and formed solid solutions over the whole range ofx. For the system (Gd1−xHox)2O3, the cationic distribution over the two non-equivalent sites 8band 24dof the space groupIa\bar{3} were found to be random for all values ofx. For (Gd1−xYbx)2O3, the distribution is random in the range 0.0 <x≤ 0.5 and preferential in the range 0.5 <x≤ 1.0. The lattice parameters are found to vary linearly with the compositionx. Replacing Gd3+and Yb3+, or Gd3+and Ho3+, by each other introduces slight changes in relative atomic coordinates. Crystallite size and microstrain analyses were performed along different crystallographic directions and both are found to vary anisotropically with the composition parameter (x). The obtained values of microstrain are correlated with the distribution of the rare earth ions over the two cationic sites of the structure. The average crystallite size ranges from 45 to 144 nm and the root mean square (r.m.s.) strain from 0.018 to 0.409 × 10−2.

In Situ Synthesis of TiC-TiB2 Composites via High Energy Ball Milling and Pressureless Sintering

2013 ◽  
Vol 401-403 ◽  
pp. 635-638
Author(s):  
Ping Luo ◽  
Shi Jie Dong ◽  
Zhi Xiong Xie ◽  
Wei Yang ◽  
An Zhuo Yangli
Keyword(s):  
Ball Milling ◽  
Milled Powder ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Sintering Process ◽  
Composite Ceramics ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
Energy Ball

TiC-TiB2 composite ceramics were successfully fabricated via planetary ball milling of 72 mass% Ti and 28 mass % B4C powders, followed by low temperature sintering process at 1200°C. The microstructure of the ball-milled powder mixtures and composite ceramics were characterized by Differential thermal analysis equipment (DTA), field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The results showed that the ball-milled powder mixtures (Ti and B4C powders) were completely transformed to TiC-TiB2 composite ceramics as the powders were milled for 60 h and sintered at 1200°C for 1 h. The formation mechanism of the TiC-TiB2 composite was discussed. The high energy ball milling and necessary sintering for the powder mixtures plays an important role in the formation of the composites.

Effect of the High Energy Milling in the Crystallite Size of WC-Co

2008 ◽  
Vol 591-593 ◽  
pp. 131-134 ◽  
Author(s):  
G.B. Pinto ◽  
S.R.S. Soares ◽  
Uilame Umbelino Gomes ◽  
Rubens Maribondo Nascimento ◽  
Antonio Eduardo Martinelli ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Milling Time ◽  
Hard Metal ◽  
High Energy ◽  
Size Distributions ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Particle Size Distributions ◽  
High Energy Milling ◽  
Grinding Media

High-energy milling has been used for production of nano-structured WC-Co powders. During the High-Energy Milling, the powders suffer severe high-energy impacts in the process of ball-to-ball and ball-to-vial wall collisions of the grinding media. Hard metal produced from nanostructured powders have better mechanical properties after appropriate sintering process. During the milling the particles size of WC and Co can be reduced and plastic deformed. In the present work, a mixture of WC-10%Co was produced by high energy milling. The starting powders of the WC (0.87 μm - Wolfran Bergau) and Co (0.93 μm - H.C.Starck) were used to produce the hard metal. The influence of the milling time on the particle size distributions and in the lattice strain was investigated. Milling time of the 2, 10, 20, 50, 70, 100 and 150 hours were used. The powders after milling were characterized by X-ray diffraction (XRD) and Scanning Electronic Microscopy (SEM). The results show that 10 h milling were enough to reduce the crystallite size of WC and the increase of the milling time reduces the crystallite size.

Characterization of Strontium Ferrites Powders Obtained by High Energy Milling

2005 ◽  
Vol 498-499 ◽  
pp. 311-315
Author(s):  
P.I. Paulin Filho ◽  
R.R. Corrêa
Keyword(s):  
Electron Microscopy ◽  
Barium Carbonate ◽  
High Energy ◽  
Milling Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Energy Milling ◽  
Transmission Electron ◽  
Strontium Ferrites

Strontium ferrites powders were obtained by high energy milling process after calcinations of iron oxide and barium carbonate. Phase formations and crystallite size was determined using X-ray diffraction. Morphology, particle size and agglomeration stages were analyzed using scanning and transmission electron microscopy. Results show particles in the range of 14 to 40 nanometers, large agglomerates and crystalline phases formation.

Phase Transformation of Cu-Mo-C Powder during Mechanical Alloying and Annealing Process

2011 ◽  
Vol 233-235 ◽  
pp. 1678-1683
Author(s):  
Ke Sheng Zuo ◽  
Sheng Qi Xi ◽  
Jing En Zhou
Keyword(s):  
Phase Transformation ◽  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Graphite Powder ◽  
High Energy ◽  
Milling Process ◽  
Carbon Powder ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray

The allotropes of graphite and activated carbon were mixed with Cu and Mo powder, respectively. And the two groups of mixtures were high-energy milled and annealed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and DSC/TG were used to investigate the phase transformation during the milling and sintering process. For both groups of powder milled, Mo was hard to dissolve in Cu, and C mainly congregated in the surface of Cu powder. When Cu-Mo-graphite powder as milled was annealed, Mo2C was formed. In comparison to Cu-Mo-graphite alloyed powder, Cu-Mo-activated carbon powder partially formed Cu oxide and Mo oxide with higher binding energy during milling process, which caused higher reduction temperature of Cu oxide and reaction temperature of Mo2C.This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

Development of Biodegradable Mg-Ti Alloy Synthesized Using Mechanical Alloying

2016 ◽  
Vol 1133 ◽  
pp. 75-79 ◽  
Author(s):  
Emee Marina Salleh ◽  
Sivakumar Ramakrishnan ◽  
Zuhailawati Hussain
Keyword(s):  
Mechanical Alloying ◽  
Milling Time ◽  
Milled Powder ◽  
Milling Process ◽  
Planetary Mill ◽  
Ti Alloy ◽  
X Ray Diffraction ◽  
Argon Flow ◽  
Diffraction Patterns ◽  
Ti Powder

The aim of this work was to study the effect of milling time on binary magnesium-titanium (Mg-Ti) alloy synthesized by mechanical alloying. A powder mixture of Mg and Ti with the composition of Mg-15wt%Ti was milled in a planetary mill under argon atmosphere using a stainless steel container and balls. Milling process was carried out at 400 rpm for various milling time of 2, 5, 10, 15 and 30 hours. 3% n-heptane solution was added prior to milling process to avoid excessive cold welding of the powder. Then, as-milled powder was compacted under 400 MPa and sintered in a tube furnace at 500 °C in argon flow. The refinement analysis of the x-ray diffraction patterns shows the presence of Mg-Ti solid solution when Mg-Ti powder was mechanically milled for 15 hours and further. Enhancements of Mg-Ti phase formation with a reduction in Mg crystallite size were observed with the increase in milling time. A prolonged milling time has increased the density and hardness of the sintered Mg-Ti alloy.

3-Dimensional Characterization of Polycrystalline Bulk Materials Using High-Energy Synchrotron Radiation

2007 ◽  
Vol 539-543 ◽  
pp. 2353-2358 ◽  
Author(s):  
Ulrich Lienert ◽  
Jonathan Almer ◽  
Bo Jakobsen ◽  
Wolfgang Pantleon ◽  
Henning Friis Poulsen ◽  
...  
Keyword(s):  
High Resolution ◽  
Synchrotron Radiation ◽  
High Energy ◽  
Mapping Technique ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
Reciprocal Space Mapping ◽  
3 Dimensional ◽  
Individual Grains

The implementation of 3-Dimensional X-Ray Diffraction (3DXRD) Microscopy at the Advanced Photon Source is described. The technique enables the non-destructive structural characterization of polycrystalline bulk materials and is therefore suitable for in situ studies during thermo-mechanical processing. High energy synchrotron radiation and area detectors are employed. First, a forward modeling approach for the reconstruction of grain boundaries from high resolution diffraction images is described. Second, a high resolution reciprocal space mapping technique of individual grains is presented.

Microstructure and superconducting properties of attrition-milled Bi2Sr2CaCu2Ox

1994 ◽  
Vol 9 (2) ◽  
pp. 297-304 ◽  
Author(s):  
J.S. Luo ◽  
H.G. Lee ◽  
S.N. Sinha
Keyword(s):  
Electron Microscopy ◽  
Milled Powder ◽  
High Energy ◽  
Double Layers ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Steel Tank ◽  
Practical Implications

The microstructure and superconducting properties of Bi2Sr2CaCu2Ox (Bi-2212) during high-energy attrition milling were investigated in detail by a combination of x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and magnetization techniques. The starting superconducting powder was milled in a standard laboratory attritor using yttria-stabilized ZrO2 balls and a stainless steel tank. After selected time increments, the milling was interrupted and a small quantity of milled powder was removed for further analysis. It was found that the deformation process rapidly refines Bi-2212 into nanometer-size crystallites, increases atomic-level strains, and changes the plate-like morphology of Bi-2212 to granular submicron clusters. At short milling times, the deformation seems localized at weakly linked Bi-O double layers, leading to twist/cleavage fractures along the {001} planes. The Bi-2212 phase decomposes into several bismuth-based oxides and an amorphous phase after excessive deformation. The superconducting transition is depressed by about 10 K in the early stages of milling and completely vanishes upon prolonged deformation. A deformation mechanism is proposed and correlated with the evolution of superconducting properties. The practical implications of these results are presented and discussed.

High-Energy Ball Milling and Sintering of Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B Powders Mixtures

2014 ◽  
Vol 802 ◽  
pp. 20-24 ◽  
Author(s):  
Lucas Moreira Ferreira ◽  
Luciano Braga Alkmin ◽  
Érika C.T. Ramos ◽  
Carlos Angelo Nunes ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Ball Milling ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
Heat Treated ◽  
Equilibrium Structures ◽  
Rotary Speed ◽  
Steel Balls

The milling process of elemental Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B (at-%) powder mixtures were performed in a planetary Fritsch P-5 ball mill using stainless steel vials (225 mL) and hardened steel balls (19 mm diameter). Ball-to-powder weight ratio of 10:1 and a rotary speed of 300 rpm were adopted, varying the milling time. Wet milling (isopropyl alcohol) for 20 more minutes was used to increase the yield powder in to the vial. Following the Ti-Ta-Si-B powders milled for 600 min were heat-treated at 1100°C for 1 h in order to obtain the equilibrium structures. The milled powders and heat-treated samples were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Supersaturated Ti solid solutions were formed during ball milling of Ti-Ta-Si-B powders while that the Ti5Si3 phase was formed after milling for 620 min of the Ta-richer powder mixture only. The particles sizes were initially increased during the initial milling times, and the wet milling provided the yield powder into the vials. A large amount of pores was found in both the sintered samples which presented the formation of the TiSS,(ss-solid solution) Ti6Si2B and TiB.

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