Disordering and amorphization of L12-type alloys by mechanical attrition

1992 ◽  
Vol 7 (11) ◽  
pp. 2971-2977 ◽  
Author(s):  
T. Benameur ◽  
A.R. Yavari
Keyword(s):  
Milling Time ◽  
Nanocrystalline Structure ◽  
Al Alloys ◽  
Heat Of Mixing ◽  
Lattice Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mechanical Attrition ◽  
Pt Alloy ◽  
Diffraction Patterns

X-ray diffraction patterns obtained during the grinding of Ni3Ge and Ni3Al alloys which at equilibrium exhibit the L12 ordered fcc structures show the emergence of a nanocrystalline structure and transformation to the disordered fcc form but little amorphization. Furthermore, the non-L12 Al2Pt alloy which also has a more strongly negative heat of mixing is easier to amorphize than the Ni3Ge and Ni3Al with L12 superstructure. This is in contrast to the Zr3Al compound (also L12-type) for which a short milling time is sufficient for obtaining complete amorphization. Variations in the aptitudes toward amorphization of the three L12-type alloys under ball-milling conditions are attributed in part to the differences in the lattice stability terms of their disordered fcc phases.

Ultrasonic Surface Mechanical Attrition of Commercially Pure Ti to Induce Nanocrystalline Surface Layer

2010 ◽  
Vol 442 ◽  
pp. 152-157 ◽  
Author(s):  
M. Mansoor ◽  
J. Lu
Keyword(s):  
Pure Titanium ◽  
Nanocrystalline Structure ◽  
Surface Mechanical Attrition Treatment ◽  
X Ray Diffraction ◽  
Annealed Condition ◽  
X Ray ◽  
Commercially Pure ◽  
Transmission Electron ◽  
Mechanical Attrition ◽  
Xrd And Tem

In the domain of incremental nanotechnology, surface mechanical attrition treatment is a technique which can transform superficial structure of a material to nanocrystalline without changing the chemical composition. This study is a part of the development and implementation of the technique by using ultrasonic vibrations. The material used is pure titanium in rolled and annealed condition. The nanocrystalline structure is characterized using X-ray diffraction (XRD), and transmission electron microscopy (TEM). The measured grain size is in the order of 5~60 nm. A correlation in the results of XRD and TEM is also discussed.

Thermal and Structural Characterization of Nanocomposite Iron Nitride - Alumina and Iron Nitride - Silica Particles

2001 ◽  
Vol 703 ◽  
Author(s):  
Ann M. Viano ◽  
Sanjay R. Mishra
Keyword(s):  
Particle Size ◽  
Milling Time ◽  
Iron Nitride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Peak ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
The One

ABSTRACTNanocomposite iron nitride based powders are known to have enhanced magnetic and other physical properties. To further explore their potential for application in various fields, we have performed a systematic study of the iron nitride - alumina and iron nitride - silica systems. Iron nitride powder of composition FexN (2 < x < 4), containing both Fe3N and Fe4N phases, was mechanically milled with Al2O3 or SiO2 powder for 4, 8, 16, 32, and 64 hours at the following compositions; (FexN)0.2(Al2O3)0.8, (FexN)0.6(Al2O3)0.4, (FexN)0.2(SiO2)0.8, and (FexN)0.6(SiO2)0.4. Differential thermal analysis and X-ray diffraction were performed to investigate thermal and structural transitions as a function of milling time. As the milling time is increased, the thermal peak corresponding to Fe4N is diminished, while the one corresponding to Fe3N is enhanced. These transitions are correlated with X-ray diffraction patterns. All XRD peaks broaden as a function of milling time, corresponding to smaller particle size. Transmission electron microscopy also reveals a decrease in particle size as the milling time in increased.

DSC-TGA Hydrogen Evaluation during Mechanical Milling of AlFe Intermetallic

2013 ◽  
Vol 755 ◽  
pp. 105-110 ◽  
Author(s):  
E. García de León M. ◽  
O. Téllez-Vázquez ◽  
C. Patiño-Carachure ◽  
G. Rosas
Keyword(s):  
Mechanical Milling ◽  
Milling Time ◽  
Hydrogen Generation ◽  
Pure Aluminum ◽  
High Energy ◽  
Milling Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns

Fe40Al60 (at%) intermetallic alloy composition was obtained by conventional casting methods and subsequently subjected to high-energy mechanical milling under different conditions of humidity. All samples were characterized by X-ray diffraction patterns (XRD), transmission electron microcopy (TEM) and DSC-TGA thermogravimetric experiments. After the milling process, the amount of hydrogen generated was determined using thermogravimetric analysis and chemical reactions (stoichiometry). All techniques confirm the formation of bayerite phase which is attributed to the hydrogen embrittlement reaction between the intermetallic material and water to release hydrogen. It was observed that the hydrogen generation is increased as the ball milling time is increased. The quantity of hydrogen evaluated is similar to that obtained in previous reported experiments with pure aluminum and some of its alloys.

Structural and Mechanical Properties of Nanostructured Fe-Mn-C Alloys Prepared by Mechanical Alloying

2018 ◽  
Vol 52 ◽  
pp. 80-87 ◽  
Author(s):  
Lounes Belaid ◽  
Meriem Bendoumia ◽  
Mohamed Dakiche ◽  
Hanane Mechri ◽  
Djaffar Dahmoun ◽  
...  
Keyword(s):  
Milling Time ◽  
Milled Powder ◽  
Nanocrystalline Structure ◽  
Hadfield Steel ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Grain Sizes ◽  
New Phase ◽  
High Manganese Austenitic Steel

The object of our research is to combine the properties of Mangalloys and nanoscale advantages in order to enhance the performance and extend the range of applications in the field of work-hardening parts such as railroad components, armor, and modern auto components. We have produced a high-manganese austenitic steel nanomaterial containing more than 12 wt% Mn, which is the level of Mn in Hadfield steel. This study experimentally determined the process of phase transitions involved in Fe–13 wt% Mn–1.2 wt% C alloy during mechano-synthesis and after subsequent annealing. The milling time ranged from 0.5 to 24 h. The unique features of the nanocrystalline structure and the changes in microstructure as a function of milling time were investigated by X-ray diffraction analysis, differential scanning calorimetry, and scanning electron microscopy coupled with EDX. The grain sizes and microstrain of the milled powder were determined. A thorough study has been done on the sample where a new phase fcc (at 24h of MA) was formed.The object of our research is to combine the properties of Mangalloys and nanoscale advantages in order to enhance the performance and extend the range of applications in the field of work-hardening parts such as railroad components, armor, and modern auto components. We have produced a high-manganese austenitic steel nanomaterial containing more than 12 wt% Mn, which is the level of Mn in Hadfield steel. This study experimentally determined the process of phase transitions involved in Fe–13 wt% Mn–1.2 wt% C alloy during mechano-synthesis and after subsequent annealing. The milling time ranged from 0.5 to 24 h. The unique features of the nanocrystalline structure and the changes in microstructure as a function of milling time were investigated by X-ray diffraction analysis, differential scanning calorimetry, and scanning electron microscopy coupled with EDX. The grain sizes and microstrain of the milled powder were determined. A thorough study has been done on the sample where a new phase fcc (at 24h of MA) was formed.

CuAl2 Intermetallic Hydrogen Evaluation after Mechanical Activation of Powders

2014 ◽  
Vol 793 ◽  
pp. 127-134 ◽  
Author(s):  
J. Luis López-Miranda ◽  
Tiberio A. Reyes-Hernández ◽  
Ares G. Hernández-Torres ◽  
J.R. Romero-Romero ◽  
R. Pérez ◽  
...  
Keyword(s):  
Mechanical Activation ◽  
Chemical Reaction ◽  
Room Temperature ◽  
Hydrogen Generation ◽  
Hydrogen Release ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminum Hydroxides ◽  
Mechanical Attrition ◽  
Diffraction Patterns

Water vapor in the air affects aluminum based intermetallic compounds to form hydrogen. We take advantage of this fact to explore the amount of hydrogen obtained from CuAl2 intermetallic after its mechanical attrition activation. For this propose, CuAl2 intermetallic alloy was first produced by conventional casting methods and then subjected to mechanical milling processing. After the mechanical activation of the CuAl2 powders, a chemical reaction between them and water was carried out at room temperature including additives such as CaO, Al and NaCl. The amount of hydrogen release was correlated with other phases produced after the chemical reaction. X-ray diffraction patterns and scanning electron microscopy studies indicates that these phases were aluminum hydroxides and cupper oxides. According to these studies, a significant presence of oxide and hydroxide products occurred in the samples with NaCl additions, indicating best capability for hydrogen generation.

scholarly journals Structural, Optical, and Photocatalytic Properties of ZnSe Nanoparticles Influenced by the Milling Time

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1125
Author(s):  
Bui Thi Thu Hien ◽  
Vu Thanh Mai ◽  
Pham Thi Thuy ◽  
Vu Xuan Hoa ◽  
Tran Thi Kim Chi
Keyword(s):  
Raman Spectra ◽  
Milling Time ◽  
Blue Emission ◽  
Near Band Edge ◽  
X Ray Diffraction ◽  
Znse Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Average Size

ZnSe nanoparticles (NPs) were prepared by combining both hydrothermal and mechanical milling methods. Transmission electron microscopy images show that fabricated ZnSe NPs with a sphere-like shape have an average size (d) in the range of 20–100 nm, affected by changing the milling time from 10 to 60 min. All the samples crystalize in zincblende-type structure without impurities, as confirmed by analyzing X-ray diffraction patterns, Raman spectra, and energy-dispersive X-ray spectroscopy. Carefully checking Raman spectra, we have observed the broadening and redshift of vibration modes as decreasing NP size, which are ascribed to extra appearance of disorder and defects. The photoluminescence study has found a blue emission at 462 nm attributed to the excitonic near-band edge and a broad defect-related emission around 520–555 nm. Increasing milling time leads to the decrease in the exciton-emission intensity, while the defect-related emissions increase gradually. Interestingly, as decreasing d, we have observed an improved photodegradation of Rhodamine B under UV irradiation, proving application potentials of ZnSe NPs in photocatalytic activity.

scholarly journals EFFECT OF ANNEALING ON MAGNETIC AND STRUCTURAL PROPERTIES OF THE NANOCRYSTALLINE Fe-Mn-Al ALLOYS

2016 ◽  
Vol 2 (1) ◽  
pp. 26
Author(s):  
K. Tarigan ◽  
D. Sebayang
Keyword(s):  
Single Phase ◽  
Milling Time ◽  
Al Alloys ◽  
Magnetic Saturation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Vibration Sample Magnetometer ◽  
X Ray Absorption ◽  
Scanning Electron

<p>In this work, the formations of Fe<sub>55</sub>Mn<sub>10</sub>Al<sub>35</sub> nanocrystalline alloys were made by using mechanical alloying (MA) technique with the milling time of 24 hrs and then annealed at 300, 500, and 700<sup>o</sup>C. The sizes and the morphology of the particles were checked by using a Scanning Electron Microscope (SEM). The magnetic properties were characterized by using a Vibration Sample Magnetometer (VSM), and it give results both of the magnetic saturation (<em>Ms</em>) and Coercivity (<em>Hc</em>) are decreased respect to annealing temperatures. Last one; the structures were characterized by using an Extended X-ray Absorption Fine Structure (EXAFS) and X-Ray Diffraction (XRD). It give results that the structures were single phase at 24 hrs milled and 300<sup>o</sup>C annealed, then the structure to be changed at 500 and 700<sup>o</sup>C. </p>

Effect of Milling Time on Consolidation of Al5083 Nanocomposite by Equal Channel Angular Pressing

2019 ◽  
Vol 969 ◽  
pp. 662-668
Author(s):  
K. Chandra Sekhar ◽  
Y. Umamaeshwar Rao ◽  
Balasubramanian Ravisankar ◽  
S. Kumaran
Keyword(s):  
Milling Time ◽  
Lattice Strain ◽  
Milled Powder ◽  
Nanocrystalline Structure ◽  
Back Pressure ◽  
Maximum Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Powders ◽  
Angular Pressing

The effect of milling time on consolidation of Al5083-5wt. % nanoyttrium oxide powders which are milled from 0-35 hours using planetary ball mill. nanocrystalline structure was observed after 10hours of milling. X-ray diffraction results reveals the formation of 57nm and 31nm for 20hr and 35hr of milling with increase in lattice strain. Circular and Elliptical morphology of milled powders were confirmed through SEM with decrease in particle size. The 90o die channel angle ECAP die was used to consolidate 20hr and 35hr milled powder aided with and without back pressure. The optical micrographs reveal the formation of fine grains. The35hr milled powder shows the maximum densification of 96% and 20hr milled powder shows maximum hardness of 82HRB was observed in 20hr milled powder. Both are consolidated for two passes in route-A and sintered at 430°C for one hour.

Origins of stored enthalpy in cryomilled nanocrystalline Zn

2001 ◽  
Vol 16 (12) ◽  
pp. 3485-3495 ◽  
Author(s):  
Xinghang Zhang ◽  
Haiyan Wang ◽  
Magdy Kassem ◽  
Jagdish Narayan ◽  
Carl C. Koch
Keyword(s):  
Structural Changes ◽  
Milling Time ◽  
Lattice Strain ◽  
Liquid Nitrogen Temperature ◽  
Temperature Differential ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Mechanical Attrition

Nanocrystalline Zn was prepared by cryomilling (mechanical attrition at liquid nitrogen temperature). Differential scanning calorimetry (DSC), x-ray diffraction, and transmission electron microscopy were used to study the structural changes and grain size distribution with milling time and subsequent annealing. Maxima in both stored enthalpy (for the low-temperature DSC peak) and lattice strain on the Zn basal planes were observed at the same milling time. Dislocation density on the basal planes is proposed as a major source for lattice strain and the measured stored enthalpy. The released enthalpy that might be due to grain growth is very small.

Spinodal Decomposition in Fe(1-X)O-Fe3o4 Sintered Ceramics.

2000 ◽  
Vol 6 (S2) ◽  
pp. 366-367
Author(s):  
A. Huerta ◽  
H. A. Calderon ◽  
M. Umemoto ◽  
M. E. Brito
Keyword(s):  
Solid Solution ◽  
Milling Time ◽  
Initial Mixture ◽  
Ceramic Materials ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Initial Content ◽  
Diffraction Patterns

Ceramic materials in the system FeO-Fe3o4 have been produced by means of mechanical milling and sintering for application of their physical properties. Starting from powder mixtures of Fe and Fe3o4 or Fe and Fe2o4, as well as pure Fe3o4, a metastable solid solution of Fe and O has been produced. The amount of Fe dissolved varies according to the milling time and its initial content in the mixture. A protective Ar atmosphere is used in all stages of the milling process in order to avoid contamination. X-ray diffraction patterns show a clear displacement of the intensity maxima as a function of the milling time, suggesting the formation of a solid solution from the initial mixture. Use of Mossbauer spectroscopy reveals an increasingly higher amount of metastable wustite (Fe(1-X) as a function of milling time i.e., 500 h and 1000 h of milling produce 67 and 74 mol % Fe(1-X)O, respectively.

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