scholarly journals Characterization of Mechanically Alloyed Nanocrystalline Fe(Al): Crystallite Size and Dislocation Density

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
M. Mhadhbi ◽  
M. Khitouni ◽  
L. Escoda ◽  
J. J. Suñol ◽  
M. Dammak

A nanostructured disordered Fe(Al) solid solution was obtained from elemental powders of Fe and Al using a high-energy ball mill. The transformations occurring in the material during milling were studied with the use of X-ray diffraction. In addition lattice microstrain, average crystallite size, dislocation density, and the lattice parameter were determined. Scanning electron microscopy (SEM) was employed to examine the morphology of the samples as a function of milling times. Thermal behaviour of the milled powders was examined by differential scanning calorimetry (DSC). The results, as well as dissimilarity between calorimetric curves of the powders after 2 and 20 h of milling, indicated the formation of a nanostructured Fe(Al) solid solution.

1993 ◽  
Vol 8 (2) ◽  
pp. 307-313 ◽  
Author(s):  
K. Aoki ◽  
A. Memezawa ◽  
T. Masumoto

An intermetallic compound c–NiZr and a mixture of elemental powders of nickel and zirconium [Ni50Zr50 (at. %)] have been mechanically ground (MG) and mechanically alloyed (MA), respectively, using a high-energy ball mill in various atmospheres. The products were characterized by x-ray diffraction, transmission electron microscopy, differential scanning calorimetry, and chemical analysis as a function of milling time. An amorphous a–NiZr alloy was prepared by both MG and MA in an argon atmosphere. By MG of NiZr, an amorphous nitride a–NiZrN0.15 was synthesized in a nitrogen atmosphere, while a crystalline hydride c–NiZrH3 was formed in a hydrogen atmosphere. On the other hand, ZrN and ZrH2 were formed by MA in a nitrogen and a hydrogen atmosphere, respectively. The amorphization reaction was observed between ZrH2 and Ni by further MA in a hydrogen atmosphere, and a mixture of a–NiZrxHy (x < 1) and ZrH2 was obtained. However, no amorphization was observed by MA between ZrN and Ni in a nitrogen atmosphere. The effects of the milling atmosphere on the phase formations during MG and MA are discussed based on the gas absorption rate.


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Hadi Jahangiri ◽  
Sultan Sönmez ◽  
M. Lütfi Öveçoğlu

The effects of milling atmosphere and mechanical alloying (MA) duration on the effective lattice parameter, crystallite size, lattice strain, and amorphization rate of the W-0.5 wt.% Ti powders were investigated. W-0.5 wt.% Ti powders were mechanically alloyed (MA’d) for 10 h and 20 h in a high energy ball mill. Moreover, morphology of the powders for various MA was analyzed using SEM microscopy. Their powder density was also measured by helium pycnometer. The dry milled agglomerated powders have spherical particle, while wet milled powders have layered morphology. Milling media and increasing of milling time significantly reduce the crystallite size. The smallest crystallite size is 4.93 nm which belonged to the dry milled powders measured by Lorentzian method after 20 hours’ MA. However, after 20 hours, MA’d powders show the biggest crystallite size, as big as 57.07 nm, measured with the same method in ethanol.


2017 ◽  
Vol 47 ◽  
pp. 79-88 ◽  
Author(s):  
Z. Hamlati ◽  
W. Laslouni ◽  
Mohammed Azzaz ◽  
M. Zergoug ◽  
D. Martínez-Blanco ◽  
...  

Ternary Fe72Al26Sn2 and Cu70Fe18Co12 alloys were obtained by mechanical alloying of pure Fe, Al, Sn, Cu and Co powders using a high energy ball mill. X-ray diffraction and electron microscopy supported by magnetic measurements have been applied to follow changes in the microstructure, phase composition and magnetic properties in dependence on milling time. With the increase of milling time all Al and Sn atoms dissolved in the bcc Fe and the final product of the MA process was the nanocrystalline Fe (Al, Sn) solid solution in a metastable state with a large amount of defects and mean crystallite size of 5 nm. However, the obtained crystallite size value is about 10 nm for the ball milled Cu70Fe18Co12 powders. The electron microscope observations show the morphology of powder particles. Magnetic properties of the nanocrystalline mechanically alloyed FeAlSn and CuFeCo were also investigated and were related to the microstructural changes.


2010 ◽  
Vol 163 ◽  
pp. 243-246 ◽  
Author(s):  
Marek Krasnowski ◽  
Tadeusz Kulik

In the present work, an elemental powder mixture of Al60Fe20Ti15Ni5 (at.%) was mechanically alloyed in a high-energy ball mill. The phase transformations occurring in the material during milling were studied with the use of X-ray diffraction. The results obtained show that an amorphous phase was formed during performed mechanical alloying process. Thermal behaviour of the milling product was examined by differential scanning calorimetry. It was found that amorphous phase crystallised above 540 °C when a heating rate of 40 °C/min was applied. On the basis of X-ray diffraction results, crystallisation product was identified as a cubic phase with the lattice parameter a0 = 11.856 Å, isomorphic with the 2 (Al2FeTi, fcc structure D8a) phase. The mean crystallite size of the crystallised 2 phase was 19 nm.


2012 ◽  
Vol 05 ◽  
pp. 496-501 ◽  
Author(s):  
S. SHEIBANI ◽  
S. HESHMATI-MANESH ◽  
A. ATAIE

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.


2005 ◽  
Vol 498-499 ◽  
pp. 146-151
Author(s):  
Y.A. Giffoni ◽  
Erika Coaglia Trindade Ramos ◽  
Ana Sofia Ramos ◽  
Hugo Ricardo Zschommler Sandim ◽  
M.T.T. Pacheco

Porous Ti-Nb alloys are promising candidates for biomedical applications. In the present study, alloy powders containing 60 wt-% Nb were prepared by high-energy milling of Nb, Ti, and/or TiH2 powders. The high-energy milling process was carried out in a planetary ball mill. The starting and as-milled materials were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). Elemental (Nb, and Ti) and TiH2 powder mixtures with composition Nb-40wt%Ti were mechanically alloyed for 2 to 30 h. The formation of a BCC Nb(Ti) solid solution by high-energy milling using elemental Ti powder to produce Nb-40Ti was observed after milling for 30 h. A HCP-Ti solid solution was formed after milling for 30 h due to the partial decomposition of titanium hydride powder mixture during high-energy milling.


2018 ◽  
Vol 2 (3) ◽  
pp. 50 ◽  
Author(s):  
David Florián-Algarín ◽  
Angelisse Ramos-Morales ◽  
Michelle Marrero-García ◽  
Oscar Suárez

This research focuses on the fabrication of aluminum wires treated with MoB2 nanoparticles and their effect on selected mechanical and thermal properties of the wires. These nanoparticles were obtained by fragmentation in a high-energy ball mill and then mechanically alloyed with pure aluminum powder to form Al/MoB2 pellets. The pellets were added to molten pure aluminum (99.5%) at 760 °C. Afterwards, the treated melt was cast into cylindrical ingots, which were cold-formed to the desired final diameter with intermediate annealing. X-ray diffraction and optical microscopy allowed characterizing the structure and microstructure of the material. The wires underwent tensile and bending tests, as well as electrical measurements. Finally, this research demonstrated how the mechanical properties of aluminum wires can be enhanced with the addition of MoB2 nanoparticles with minimal effects on the material resistivity.


2018 ◽  
Vol 54 ◽  
pp. 136-145
Author(s):  
A. El Mohri ◽  
M. Zergoug ◽  
K. Taibi ◽  
M. Azzaz

Nanocrystalline Fe90Mg10 alloy samples were prepared by mechanical alloying process using planetary high energy ball mill. The prepared powders were characterized using differential thermal analysis (DTA), X-ray diffraction technique (XRD) at high temperature, transmission electron microscopy (TEM), and the vibrating sample magnetometer (VSM). Obtained results are discussed according to milling time. XRD at high temperature results also indicated that when the milling time increases, the lattice parameter and the mean level of grain size increase, whereas the microstrains decrease. The result of the observation by the TEM of the Fe-Mg powders prepared in different milling time, coercive fields derived and Saturation magnetization derived from the hysteresis curves in high temperature are discussed as a function of milling time.


2013 ◽  
Vol 203-204 ◽  
pp. 272-275
Author(s):  
Marek Krasnowski ◽  
Tadeusz Kulik

An elemental powder mixture corresponding to the Al3Ni2 phase stoichiometry was subjected to mechanical alloying in a high-energy ball mill. Products of this process after various milling times were investigated by differential scanning calorimetry. The phase transformations occurring in the material throughout milling and during heating in a calorimeter were investigated by X-ray diffraction method. This study revealed that a metastable nanocrystalline NiAl intermetallic phase was formed during the mechanical alloying process. Heating of the synthesised powders in the calorimeter caused phase transformations, the product of which was an equilibrium Al3Ni2 intermetallic phase or a mixture of NiAl, Al3Ni2 and Al3Ni intermetallic phases, depending on the milling time and the temperature up to which the material was heated.


2014 ◽  
Vol 802 ◽  
pp. 66-71
Author(s):  
Rodrigo Estevam Coelho ◽  
D.B. Silvany ◽  
M.D.C. Sobral ◽  
M.C.A. Silva

In this works, aluminum scraps powders were mixed with commercial graphite and mechanically alloyed in a high-energy ball mill and subsequently powders sintering. The initial grinding of aluminum scraps for 2 hours and then mixed with commercial graphite powder at a proportion of (y)Al-(x)C (wt%) (x = 1, 5 e 10, 25). The mixture of aluminum and graphite powders was processed for a time at 5 hours of milling. The samples were sintered at a temperature of 750°C and 1000°C. Samples were analyzed by scanning electron microscopy and X-ray diffraction. The results of this study were to find important parameters of composition and sintering, because the increase in concentration of carbon in the aluminum indicates that the material may have different applications.


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