Thermal and Phase Evolutions of As-Milled Powders Fabricated by Mechanical Alloying in the TiH2-C System

2006 ◽  
Vol 510-511 ◽  
pp. 366-369 ◽  
Author(s):  
Sung Yeal Bae ◽  
In Sup Ahn ◽  
Tek Kyung Sung ◽  
Dong Kyu Park
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Mechanical Alloying ◽  
Milled Powder ◽  
Hydrogen Gas ◽  
Carbon Powder ◽  
Unstable Phase ◽  
Particle Size Analyzer ◽  
Vacuum Atmosphere ◽  
Milled Powders

Nano-TiC powders were fabricated for mechanical alloying (MA) by shaker mill using the TiH2 powders mixed carbon powder. For mechanical alloying, titanium hydride was easily breaking alloy and easily decomposed titanium particles and hydrogen gas. The decomposition titanium powders in TiH2 powders were very fine particle size and unstable phase. And it easily reacted to carbon ;(TiH2 + C 􀃆 TiC + H2). The effects of mechanical allyoing, morphology, phase and particle size were evaluated with X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), TG/DTA and particle size analyzer. As-milled powders for 10 hours were successfully synthesized powders of TiC phase, mean particle 300nm size. And as-milled powder for 1 hour was included unstable phase, was annealed for 1 hour at 400°C-1300°C in 1x10-3torr vacuum atmosphere. Unstable phase was changed to recrystallize phase by heat treatment. After heat treatment for 1hour using as-milled powders, it was included many types of titanium oxide at temperature below 1000°C, was formed single phase of TiC at temperature over 1000°C.

Intermetallic Effects on the Ductility of Sintered Aluminium

2008 ◽  
Vol 587-588 ◽  
pp. 380-384
Author(s):  
Jesus Cintas ◽  
José A. Rodríguez ◽  
Francicso Gomez Cuevas ◽  
José M. Gallardo
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Intermetallic Particle ◽  
Quantitative Metallography ◽  
Mechanically Alloyed ◽  
Aluminium Powder ◽  
Attrition Milling ◽  
Different Temperatures ◽  
Alloyed Aluminium ◽  
Milled Powders

Mechanically alloyed aluminium powder was prepared by attrition-milling for 10 hours in the presence of a wax. Milled powders were annealed in vacuum at different temperatures (500, 575, 600, 625 and 650°C). Compacts were consolidated starting from unannealed and from 600°Cannealed powders. Studies by SEM microfractography and quantitative metallography, to investigate the influence of Fe-Al intermetallics on compacts fracture, have been carried out. It is concluded that fracture takes place at regions where the area occupied by the intermetallics is high and intermetallics particles are big. Intermetallic particle size can be controlled by an appropriated heat treatment.

The Mechanical Alloying of Magnetite Concentrate with Biochar

2020 ◽  
Vol 10 (2) ◽  
pp. 116-125
Author(s):  
Elif Aranci Öztürk ◽  
Mustafa Boyrazli ◽  
Mehmet Deniz Turan ◽  
Murat Erdemoğlu
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Grain Size ◽  
Mechanical Alloying ◽  
Milled Powder ◽  
Spherical Particles ◽  
Size Analysis ◽  
Biomass Waste ◽  
Magnetic Separator ◽  
Magnetite Concentrate

Aim: In this work, the effect of milling time on the mechanical alloying of the mixture containing the magnetite concentrate and biomass waste was investigated. Materials and Methods: The ore’s grade consisting of hematite and magnetite minerals was increased from 49.87% Fe to 67.29% Fe using the low intensity wet magnetic separator. Biomass waste which was supplied from ÇAYKUR black tea facilities, used as a carbon source was subjected to carbonization processes at 800°C for 1440 min. After the carbonization process, the carbon and sulphur contents of the biomass were measured as 94.68% and 0.03%, respectively. For the mechanical alloying process, a mixture consisting of magnetite concentrate with a grain size of -45 μm and biomass which was added two times the amount of carbon required for the reduction of magnetite to metallic iron was used. Result: After the mechanical alloying process which was carried out at different times, it was observed in the particle size analysis that the particle size of 90% of the mixture was reduced to about 4 μm. In SEM (Scanning Electron Microscopy) images, cube-like particles along with the spherical particles were observed depending on the mechanical alloying times. After 45 minutes of alloying, it was observed that the carbonized product milled together with magnetite concentrate was partially integrated into the crystal structure. Conclusion: The carbonized tea plant waste milled together with magnetite concentrate was partially integrated into the crystal structure. And the mechanical alloying provide to increase in the specific surface area in parallel with the grain size decrease in the study. Thus, in the later stage of the study, the milled powder acquired more ability to react.

Preparing Amorphous/Nanocrystalline TiNbZrTaFe Powder by Mechanical Alloying

2015 ◽  
Vol 816 ◽  
pp. 671-675
Author(s):  
Li Ming Zou ◽  
Yi Xiang Cai
Keyword(s):  
Mechanical Alloying ◽  
Milled Powder ◽  
Nanocrystalline Structure ◽  
Alloy System ◽  
Amorphous Structure ◽  
Liquid Region ◽  
Matrix Composites ◽  
Fe Content ◽  
Glass Matrix Composites ◽  
Milled Powders

(Ti69.7Nb23.7Zr4.9Ta1.7)100-xFex(x=0, 2, 6, and 10) nanocrystalline, nanocomposite and amorphous powders were synthesized by mechanical alloying from blended element powder. The structural transition for the milled powders was confirmed by X-ray diffraction (XRD). Results shows with the increasing Fe content in alloy system, the glass forming ability become larger. Only forx=10, it can obtain nearly completely amorphous structure with wide super cooled liquid region (△Tx=122 K). Forx=2 and 6, residual nanocrystals of the β-Ti structure dispersed in the amorphous matrix. Forx=0, the milled powder has full nanocrystalline structure. These as-milled powders offer the potential to fabricating the bulk glass material or nanocrystal/glass matrix composites by powder metallurgy for biomedical use.

scholarly journals Preparation of PAN Spinning Solution with Fine Dispersion of Cellulose Microparticles

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Jee-Woo Yang ◽  
Jong Sung Won ◽  
Da Young Jin ◽  
Ji Eun Lee ◽  
Won Ho Park ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Carbon Fiber ◽  
Physical Method ◽  
Heat Treating ◽  
Optimum Conditions ◽  
Pan Fiber ◽  
Particle Size Analyzer ◽  
Milling Method ◽  
Ft Ir

This study suggested the optimum conditions for the stable dispersion of cellulose microparticles in PAN spinning dope, which was prepared for spinning the fiber. Many research studies have investigated methods for preparing a variety of carbon fiber precursors in an attempt to control their characteristics according to the applications. In order to prepare PAN fiber that contains fine cellulose particles, it is important to create a uniformly dispersed spinning dope. Minimization of the cellulose particle size was subjected to heat treatment at various temperatures in order to reduce the cohesive force from the hydrogen bonds between the cellulose molecules. Carbonized cellulose microparticles were obtained for efficient dispersion using the physical method and the sedimentation method. Several instrumental analyses were conducted to study the characteristics of the particles and solutions with SEM, FT-IR, XRD, and a particle size analyzer. From the results, the dispersion of the PAN spinning dope with a chemical treatment was superior to the milling method followed by heat treatment. In this study, heat-treating cellulose microparticles at 400°C was found to be the most effective method.

Cryomilling and Characterization of Ti/Al2O3 Powders

2018 ◽  
Vol 281 ◽  
pp. 285-290
Author(s):  
Jun Yan Wu ◽  
Qian Liu ◽  
Zhi Hao Wang ◽  
Zhi Wang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Grain Size ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Particle Size Analyzer ◽  
Distribution Phase ◽  
Xrd And Tem ◽  
Milled Powders

In order to prevent the oxidation of Ti, which ultimately leads to the generation of intermetallic compound Ti3Al, a new method of cryomill in liquid nitrogen was used to deal with the Ti/Al2O3 powders. The size distribution, phase composite and microstructure of the powders were analyzed using laser particle size analyzer, XRD, and TEM, respectively. Then, the performances of Ti/Al2O3 cermet sintered using cryomilled powders and room temperature milled powders were compared. The results show that, with the increase of cryomilling time, the grain size decreases shapely and high reactivitive nanoscale powders are finally obtained. With the cryomilling in liquid nitrogen, the Ti-N bonds are formed, which successfully prevent the oxidation of Ti. Ti/Al2O3 cermet sintered using cryomilled powders shows higher density, better mechanical properties than that using RT milled powders.

Bulk Al Materials from Back Pressure Equal Channel Angular Consolidation of Mechanically Milled Particles

2008 ◽  
Vol 584-586 ◽  
pp. 428-433 ◽  
Author(s):  
Masahiro Kubota ◽  
Xiao Lin Wu ◽  
Wei Xu ◽  
Kenong Xia
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Bulk Material ◽  
Milled Powder ◽  
Back Pressure ◽  
Full Density ◽  
Isothermal Heat Treatment ◽  
Pure Aluminium ◽  
Bulk Materials ◽  
Milled Powders

Mechanically milled pure aluminium powders were fabricated into bulk materials using back pressure equal channel angular consolidation (BP-ECAC) for four or eight passes at 373K. The bulk materials consolidated from 0 h and 4 h mechanically milled powders were characterised by Vickers hardness tests and density measurements. Thermal stability of the consolidated bulk materials was evaluated by isothermal heat treatments at 673K. The as-consolidated bulk material from the 0 h milled (i.e. unmilled) powder showed nearly full density. However, full density was not obtained with the 4 h milled powder even after eight passes. The HV values for the as-consolidated materials fabricated from the 0 h and 4 h milled powders after four passes and from the 4 h milled powder after eight passes were 57, 121 and 136, respectively. Softening was observed in the bulk material consolidated from the 0 h milled powder during the isothermal heat treatment. However, the hardness of the bulk materials consolidated from the 4 h milled powders after four and eight passes increased to maximum values of 137 and 141 after heat treatment for 28 h and 8 h at 673K, respectively. The maximum hardness was maintained for up to 100 h at 673K in both materials. The hardening and thermal stability in the bulk materials from the milled powders are attributable to dispersion strengthening of Al4C3 particles formed by solid-state reaction during the isothermal heat treatment.

Effect of Heat Treatment on Chemical Structure of a Bio-Filler from Vetiver Grass

2011 ◽  
Vol 410 ◽  
pp. 71-74 ◽  
Author(s):  
Wimonlak Sutapun ◽  
Yupaporn Ruksakulpiwat ◽  
Nitinat Suppakarn
Keyword(s):  
Heat Treatment ◽  
Thermal Decomposition ◽  
Particle Size ◽  
Crystalline Structure ◽  
Chemical Structure ◽  
Fiber Surface ◽  
Thermogravimetric Analyzer ◽  
Heat Treated ◽  
Particle Size Analyzer ◽  
Ftir Spectrometer

In this work, the effect of heat treatment on chemical and crystalline structure of vetiver powder was studied. The vetiver powder was heat treated at 170°C, the temperature below thermal decomposition of hemicellulose, for 2-6 hours. The chemical structure, crystalline structure, and thermal decomposition of untreated and heat-treated vetiver were examined via FTIR spectrometer X-ray diffractometer, and thermogravimetric analyzer, respectively. In addition, the particle size and size distribution, fiber surface, and specific surface area were investigated by particle size analyzer, scanning electron microscope, and BET surface analyzer, repectively. It was founded that some waxes, lignin, and hemicellulose were removed by the thermal treatment. This resulted in smaller particle size of heat-treated vetivers. In addition, moisture content was minimized from 7 to 4 wt% by the treatment. However, removal of those compositions did not influence crystal structure of cellulose and surface functional groups of heat-treated vetiver.

Mechanical Alloying and Sintering of Ti-10Wt.% Mg Powders

2009 ◽  
Vol 618-619 ◽  
pp. 105-108 ◽  
Author(s):  
Christopher Machio ◽  
D. Nyabadza ◽  
Hilda Kundai Chikwanda ◽  
M. Phasha ◽  
V.M. Sibanda
Keyword(s):  
Solid Solution ◽  
Particle Size ◽  
Mechanical Alloying ◽  
Particle Size Analysis ◽  
Powder Alloy ◽  
Size Analysis ◽  
Cold Compaction ◽  
Partial Decomposition ◽  
Milled Powders

A Ti-10wt.%Mg powder alloy has been produced by mechanical alloying. Elemental powders of Ti and Mg were ball milled in a Zoz-Simoloyer CM01 for 16 and 20 hours under argon. Mechanical alloying was followed by XRD, SEM and particle size analysis. Test specimens of the milled powders were produced by cold compaction and sintering (under argon). The milling resulted into a fcc TiMg solid solution for both milling durations. Sintering leads to a partial decomposition of the fcc TiMg to hcp TiMg and Ti.

Preparation of Medium-Sized Tungsten Particles via the New Method

2012 ◽  
Vol 562-564 ◽  
pp. 212-215
Author(s):  
Xiao Ming Fu
Keyword(s):  
Particle Size ◽  
Tungsten Oxide ◽  
Hydrogen Gas ◽  
Dew Point ◽  
Volume Percent ◽  
Argon Gas ◽  
Oxidation Reduction ◽  
Particle Size Analyzer ◽  
Tungsten Powders ◽  
Scanning Electron

Medium-sized tungsten particles are obtained through circulatory oxidation-reduction twice. The samples are characterized by laser particle size analyzer and scanning electron microscope (SEM). Blue tungsten oxide (BTO) is prepared with ammonium paratungstate (APT) in the argon gas. Tungsten powders are obtained with BTO through deoxidation in the hydrogen gas (Rate of purity: 99.99%, dew point: -40°C), and tungsten powders are oxidized in the air. Tungsten oxide WO3) is reduced into tungsten powders in hydrogen gas again. The routes are repeated. The volume percent content of medium-sized tungsten powders between 3 μm and 10 μm is 83.86 %.

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