Effect of AlCl3 Addition in Processing of TiAl-Al2O3 Nano-Composite via Mechanical Alloying

2011 ◽  
Vol 264-265 ◽  
pp. 626-630 ◽  
Author(s):  
S. Alamolhoda ◽  
Saeed Heshmati-Manesh ◽  
Abolghasem Ataie ◽  
A. Badiei
Keyword(s):  
High Energy ◽  
Control Agent ◽  
Cold Welding ◽  
Tio2 Powder ◽  
Process Control Agent ◽  
Nano Composite ◽  
Fine Grained ◽  
Al2o3 Composite ◽  
Crystallite Sizes ◽  
Energy Ball

In this paper, effect of AlCl3 addition as process control agent (PCA) during high energy ball milling of Al and TiO2 powder mixture was studied. This mechanical activation is aimed at to synthesize an ultra fine grained TiAl/Al2O3 composite. Experimental results show that AlCl3 significantly prevents severe cold welding of Al particles to milling media. Sublimation of this compound by local temperature increase due to balls collisions seems to be the main reason in prevention of severe cold welding. Samples were characterized by XRD, SEM and DTA. Mean crystallite sizes in particles of this sample and those milled with no PCA and milled with stearic acid were calculated and the results showed that smaller crystallite size is obtained in presence of AlCl3. However, DTA results revealed that addition of AlCl3, shifts aluminothermic reduction of TiO2 by Al to higher temperatures and therefore, final composite phases form at higher temperatures. Phase evolutions during further heat treatment of the powder sample milled with AlCl3 were also thoroughly studied.

ROLE OF PROCESS CONTROL AGENT ON MECHANICAL ALLOYING OF NANO STRUCTURED TiAl-BASED ALLOY

2008 ◽  
Vol 22 (18n19) ◽  
pp. 2933-2938 ◽  
Author(s):  
H. BAHMANPOUR ◽  
S. HESHMATI-MANESH
Keyword(s):  
Process Control ◽  
Stearic Acid ◽  
Milled Powder ◽  
High Energy ◽  
Control Agent ◽  
X Ray Diffraction ◽  
Process Control Agent ◽  
Crystallite Sizes ◽  
Energy Ball ◽  
Milled Powders

High energy ball milling was performed on a mixture of titanium and aluminum elemental powders with a composition of Ti -48(at.%) Al . Stearic acid was added to this powder mixture as a process control agent (PCA) to study its effect on the microstructure evolution and crystallite size of the milled powder after various milling times. Phase compositions and morphology of the milled powders were evaluated using X-ray diffraction and scanning electron microscopy. Crystallite sizes of milled powders were determined by Cauchy-Gaussian approach using XRD profiles. It was shown that addition of 1wt.% of stearic acid not only minimizes the adhesion of milling product to the vial and balls, but also reduces its crystallite sizes. It has also a marked effect on the morphology of the final product.

An Investigation of the use of Stearic Acid as a Process Control Agent in High Energy Ball Milling of Nb-Al and Ni-Al Powder Mixtures

2003 ◽  
Vol 416-418 ◽  
pp. 144-149 ◽  
Author(s):  
Cláudio José da Rocha ◽  
Ricardo Mendes Leal Neto ◽  
Valéria S. Gonçalves ◽  
L.L. Carvalho ◽  
Francisco Ambrozio Filho
Keyword(s):  
Process Control ◽  
Stearic Acid ◽  
Ball Milling ◽  
High Energy ◽  
Control Agent ◽  
High Energy Ball Milling ◽  
Process Control Agent ◽  
Powder Mixtures ◽  
Energy Ball ◽  
Al Powder

Synthesis by High-Energy Ball Milling of MgH2-TiFe Composites for Hydrogen Storage

2017 ◽  
Vol 899 ◽  
pp. 13-18 ◽  
Author(s):  
Ricardo Mendes Leal Neto ◽  
Rafael de Araújo Silva ◽  
Ricardo Floriano ◽  
Graziele Cristina Seco Coutinho ◽  
Railson Bolsoni Falcão ◽  
...  
Keyword(s):  
Ball Milling ◽  
Hydrogen Absorption ◽  
Hydrogen Desorption ◽  
High Energy ◽  
Control Agent ◽  
High Energy Ball Milling ◽  
Absorption Kinetics ◽  
Particle Size Reduction ◽  
Milled Sample ◽  
Energy Ball

The aim of this work is to investigate the influence of some processes variables on the microstructure and hydrogen absorption kinetics of MgH2 - X wt.% TiFe composites. Samples were synthesized by high-energy ball milling in a planetary (X = 40, 50, 60) and shaker mill (X = 40) under high-purity argon atmosphere. Commercial MgH2 instead of Mg powder was used in order to reduce adherence on the vial and balls. TiFe powder was previously produced by ball milling a mixture of TiH2 and Fe powders followed by a reaction synthesis at 600oC. Milled composites samples were characterized by XRD and SEM analysis. Milling time was preliminary investigated (X = 40) in the planetary ball mill (6 to 36h). TiFe particle size reduction was shown to be difficult since they are surrounded by MgH2 matrix. Strong particle reduction was obtained by using a shaker mill only for 2 hours and adding cyclohexane as process control agent. No reaction between MgH2 and TiFe compound was observed in any milled sample. Hydrogen absorption kinetics measurements of the as-milled samples were conducted on an Sieverts' type apparatus at room temperature after hydrogen desorption at 350oC under vacuum. The best hydrogen kinetics (3 wt% at the first hour) was attained by the planetary milled sample (36 h). Higher hydrogen capacity was observed for the sample milled in the shaker mill (4.0 wt.%), but only after 13h.

ROLE OF PROCESS CONTROL AGENTS ON MILLING BEHAVIOR OF Al AND TiO2 POWDER MIXTURE TO SYNTHESIZE TiAl/Al2O3 NANO COMPOSITE

2012 ◽  
Vol 05 ◽  
pp. 638-645 ◽  
Author(s):  
S. ALAMOLHODA ◽  
S. HESHMATI-MANESH ◽  
A. ATAIE ◽  
A. BADIEI
Keyword(s):  
Process Control ◽  
Tio2 Powder ◽  
Nano Composite ◽  
Powder Mixtures ◽  
Gaussian Method ◽  
Opposite Behavior ◽  
Crystallite Sizes ◽  
The Mean ◽  
Milled Powders

In this study effect of adding various process control agents (PCAs) to powder mixtures of Al and TiO 2 which are mechanically activated so as to form TiAl - Al 2 O 3 nano-composite have been investigated. Phase constitutions and morphology of the milled powders were evaluated by XRD and SEM techniques, respectively. The mean crystallite sizes of the milled powders were calculated by Cauchy-Gaussian method. Thermal behavior of the milled powders was also studied by DTA to investigate formation of the final phases. The results showed that the mean crystallite size of the milled powders in the presence of PCAs was smaller than that of the sample milled without PCA addition. DTA traces showed that addition of PCAs retards the reduction of TiO 2 by Al . In samples milled in presence of PCA, the reductive reaction generally took place after melting of Al particles whereas the sample milled without PCA addition showed an opposite behavior. Also, in comparison with the sample milled with no PCA addition, in other samples the reductive reaction took place at relatively lower temperatures.

SYNTHESIS OF NANO-CRYSTALLINE Cu-Cr ALLOY BY MECHANICAL ALLOYING

2012 ◽  
Vol 05 ◽  
pp. 496-501 ◽  
Author(s):  
S. SHEIBANI ◽  
S. HESHMATI-MANESH ◽  
A. ATAIE
Keyword(s):  
Mechanical Alloying ◽  
Structural Evolution ◽  
High Energy ◽  
Lattice Parameter ◽  
Control Agent ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Nano Crystalline ◽  
High Energy Ball Mill ◽  
Energy Ball

In this paper, the influence of toluene as the process control agent (PCA) and pre-milling on the extension of solid solubility of 7 wt.% Cr in Cu by mechanical alloying in a high energy ball mill was investigated. The structural evolution and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The solid solution formation at different conditions was analyzed by copper lattice parameter change during the milling process. It was found that both the presence of PCA and pre-milling of Cr powder lead to faster dissolution of Cr . The mean crystallite size was also calculated and showed to be about 10 nm after 80 hours of milling.

scholarly journals Fabrication of Al2O3/ZrO2 Micro/Nano-Composite Prepared by High Energy Ball Milling

2001 ◽  
Vol 42 (6) ◽  
pp. 1119-1123 ◽  
Author(s):  
Masaaki Nagashima ◽  
Koji Maki ◽  
Motozo Hayakawa
Keyword(s):  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Nano Composite ◽  
Energy Ball
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