scholarly journals Evolution of crystallite size, lattice parameter and internal strain in Al precipitates during high energy ball milling of partly amorphous Al87Ni8La5 alloy

2014 ◽  
Vol 604 ◽  
pp. 27-33 ◽  
Author(s):  
M. Dittrich ◽  
G. Schumacher
Keyword(s):  
Crystallite Size ◽  
Ball Milling ◽  
High Energy ◽  
Lattice Parameter ◽  
High Energy Ball Milling ◽  
Internal Strain ◽  
Energy Ball

Synthesis, Characterization, and ECAP Consolidation of Carbon Nanotube Reinforced AA 4032 Nanocrystalline Composites Produced by High Energy Ball Milling

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
M. S. Senthil Saravanan ◽  
S. P. Kumaresh Babu
Keyword(s):  
Carbon Nanotubes ◽  
Crystallite Size ◽  
Ball Milling ◽  
Base Alloy ◽  
Arc Discharge ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Nanocrystalline Powders ◽  
Peak Broadening ◽  
Energy Ball

In the present work, multiwalled carbon nanotubes (MWNTs) were synthesized by electric arc discharge method in open air atmosphere. The synthesized nanotubes were subjected to multistep purification followed by characterization using Raman spectroscopy and transmission electron microscopy (TEM). These carbon nanotubes (CNTs) have inner and outer diameters of the order of 3.5 nm and 16 nm with an aspect ratio of 63. AA 4032 nanocomposites reinforced with MWNTs were produced by high energy ball milling using elemental powder mixtures. X-ray diffraction (XRD) and scanning electron microscope (SEM) studies showed different phases of composite with and without CNTs. The crystallite size and lattice strain were calculated using an anisotropic model of Williamson–Hall peak broadening analysis, which showed in decreased crystallite size with increasing milling time. TEM studies reveal that the MWNTs were uniformly distributed in the matrix. Thermal stability of the nanocrystalline powders was studied using a differential thermal analyzer (DTA). The mechanically alloyed powders were consolidated using a novel method called equal channel angular pressing (ECAP) at room temperature. The consolidated samples were sintered at 480 °C in argon atmosphere for 90 min. ECAP method was investigated as an alternative to conventionally sintered powder composites. CNT addition has shown significant improvement in the hardness of the system, even though the observed density is relatively low compared with a base alloy. Thus, the results show that ECAP enables sufficient shear deformation results in good metallurgical bonds between particles at lower compaction pressures. Hence, it is proven that ECAP can be effectively used as one of the consolidation technique especially for powders that are difficult to consolidate by other means.

Preparation of C/Cu Composite Powders by High-Energy Ball-Milling

2011 ◽  
Vol 319-320 ◽  
pp. 61-63 ◽  
Author(s):  
Xiu Yan Guo ◽  
Guo Jin Ma ◽  
Shi Kun Xie ◽  
Rong Xi Yi ◽  
Zhi Gao
Keyword(s):  
Ball Milling ◽  
Graphite Powder ◽  
High Energy ◽  
Lattice Parameter ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Mixed Powder ◽  
X Ray ◽  
Energy Ball

Cu-4% mixed-powder consisting of rough copper powder and graphite powder was separately mechanical alloyed by high-energy ball milling. The phases and micrograph of these powders were determined by X-ray diffraction and scanning electron microscopy (SEM). The results show an increase in the lattice parameter of copper with milling times, up to a saturation value of about 24h; There was an absence of graphite reflections from X-ray diffractograms after longer milling times.

Hydrogen in Metallic Nanostructures

2007 ◽  
Vol 555 ◽  
pp. 327-334 ◽  
Author(s):  
R.A. Andrievski
Keyword(s):  
Physical Properties ◽  
Crystallite Size ◽  
Ball Milling ◽  
High Energy ◽  
Structural Features ◽  
Metallic Nanostructures ◽  
High Energy Ball Milling ◽  
Universal Method ◽  
Characterization Methods ◽  
Energy Ball

Features of hydrogen nanostructure synthesis are described as applied to metals (Mg and Pd) and intermetallics (Mg2Ni, FeTi and LaNi5). Attention is focused on the high-energy ball milling as a universal method for hydrogen nanostructure preparation. The effect of crystallite size, absorption/desorption properties of Pd - H2, Mg2Ni - H2, TiFe - H2 and Mg - H2 systems are characterized in detail. Structural features and some physical properties of nanohydrides studied by different independent characterization methods are considered.

High-Energy Ball Milling Conditions in Formation of NiTiCu Shape Memory Alloys

2021 ◽  
pp. 1-7
Author(s):  
Tomasz Goryczka ◽  
Piotr Salwa ◽  
Maciej Zubko
Keyword(s):  
Chemical Composition ◽  
Shape Memory ◽  
Crystallite Size ◽  
Ball Milling ◽  
Average Crystallite Size ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Energy Ball ◽  
Average Size ◽  
Grinding Time

The properties and the shape memory effect depend, among other things, on chemical composition, as well as the method of shape memory alloy (SMA) production. One of the manufacturing methods that leads to the amorphous/nanocrystalline SMA is high-energy ball milling combined with annealing. Using this technique, an SMA memory alloy, with the nominal chemical composition of Ni25Ti50Cu25, was produced from commercial elemental powders (purity −99.7%). The structure and morphology were characterized (at the various stages of its production) by the use of X-ray diffraction, as well as electron microscopy (both scanning and transmission). Choosing the appropriate grinding time made it possible to produce an NiTiCu alloy with a different crystallite size. Its average size changed from 6.5 nm (after 50 h) to about 2 nm (100 h). Increasing the grinding time up to 140 h resulted in the formation of areas that showed the B19 martensite and the Ti2(Ni,Cu) phase with the average crystallite size of about 6 nm (as milled). After crystallization, the average size increased to 11 nm.

Possible evidence for the stabilization of β–carbon nitride by high-energy ball milling

1999 ◽  
Vol 14 (6) ◽  
pp. 2488-2499 ◽  
Author(s):  
Y. Fahmy ◽  
T. D. Shen ◽  
D. A. Tucker ◽  
R. L. Spontak ◽  
C. C. Koch
Keyword(s):  
Ball Milling ◽  
Photoelectron Spectroscopy ◽  
Energy Levels ◽  
Hexagonal Lattice ◽  
High Energy ◽  
Lattice Parameter ◽  
High Energy Ball Milling ◽  
X Ray ◽  
Liquid Phases ◽  
Energy Ball

The possibility of stabilizing the theoretically predicted β–C3N4 phase by high-energy ball milling is investigated. Charges of graphitic carbon were milled with and without minor alloying additions under different atmospheric media, namely gas and/or liquid phases of nitrogen, air, or ammonia. Milling was performed at either of two energy levels for periods of up to 48 h. The β–C3N4 phase was found to exist as small crystallites in a matrix of primarily amorphous carbon at volume fractions estimated between 5 and 10 at.%. High-resolution electron diffraction and x-ray diffraction indicate that the crystalline nature of the C3N4 phase corresponds with a hexagonal lattice with a = 6.46 Å and c/a = 0.374, which are within 2% of the theoretically calculated lattice parameter values. Analysis of electron energy-loss spectroscopy (EELS), x-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectra verify the presence of chemically bonded carbon and nitrogen with chemical states reflecting combined sp2 and sp3 hybridization. Chemical analysis confirms nitrogen enrichment at levels consistent with the C3N4 stoichiometry and the estimated degree of stabilization. The possible mechanism(s) responsible for the stabilization of the β–C3N4 phase are briefly discussed.

On the crystallite size refinement of ZrB2 by high-energy ball-milling in the presence of SiC

2011 ◽  
Vol 31 (13) ◽  
pp. 2407-2414 ◽  
Author(s):  
V. Zamora ◽  
A.L. Ortiz ◽  
F. Guiberteau ◽  
M. Nygren ◽  
L.L. Shaw
Keyword(s):  
Crystallite Size ◽  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Size Refinement ◽  
Energy Ball

High Energy Planetary Ball Milling of SiC Powders

2007 ◽  
Vol 351 ◽  
pp. 7-14 ◽  
Author(s):  
Yu Bai Pan ◽  
Zheng Ren Huang ◽  
Dong Liang Jiang ◽  
Léo Mazerolles ◽  
D. Michel ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Ball Milling ◽  
Average Crystallite Size ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Fine Powders ◽  
Sic Ceramics ◽  
Sem And Tem ◽  
Planetary Ball Milling ◽  
Energy Ball

The effects of high-energy ball milling on SiC powders were studied using a planetary apparatus. Conditions to obtain nanostructured SiC powders with an average crystallite size of 4 nm were determined and powders were characterized by XRD, SEM and TEM analyses. This process was applied to prepare fine powders leading to dense SiC ceramics by sintering at 1900oC for 30 minutes under 30 MPa in argon.

Preparation of C/Cu Composite Powders by High-Energy Ball Milling

2011 ◽  
Vol 121-126 ◽  
pp. 1049-1052
Author(s):  
Xiu Yan Guo ◽  
Guo Jin Ma ◽  
Shi Kun Xie ◽  
Rong Xi Yi
Keyword(s):  
Ball Milling ◽  
Graphite Powder ◽  
High Energy ◽  
Lattice Parameter ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Mixed Powder ◽  
X Ray ◽  
Energy Ball

Cu-4%C mixed-powder consisting of rough copper powder and graphite powder was separately mechanical alloyed by high energy ball milling. The phases and micrograph of these powders were determined by X-ray diffraction and scanning electron microscopy (SEM). The results show that increase of the lattice parameter of copper with milling times, up to a saturation value of about 24h; The absence of graphite reflections in X-ray diffract grams for longer milling times.

Crystallite Size Refinement of ZrB2by High-Energy Ball Milling

2009 ◽  
Vol 92 (12) ◽  
pp. 3114-3117 ◽  
Author(s):  
Carlos A. Galán ◽  
Angel L. Ortiz ◽  
Fernando Guiberteau ◽  
Leon L. Shaw
Keyword(s):  
Crystallite Size ◽  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Size Refinement ◽  
Energy Ball

Enhancement in Thermoelectric Figure-of-merit of n-type Si-Ge Alloy Synthesized Employing High Energy Ball Milling and Spark Plasma Sintering

2013 ◽  
Vol 1490 ◽  
pp. 51-56 ◽  
Author(s):  
Sivaiah Bathula ◽  
M. Jayasimhadri ◽  
Ajay Dhar ◽  
M. Saravanan ◽  
D. K. Misra ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Ball Milling ◽  
Spark Plasma Sintering ◽  
Figure Of Merit ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Sintered Alloy ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball

ABSTRACTIn the present study, we report the enhancement in figure-of-merit (ZT) of nanostructured n-type Silicon-Germanium (Si80Ge20) thermoelectric alloy synthesized using high energy ball milling followed by spark plasma sintering (SPS). After 90 h of ball milling of elemental powders of Si, Ge and P (2 at.%), a complete dissolution of Ge in Si matrix has been observed forming the nanostructured n-type Si80Ge20 alloy powder. X-ray diffraction analysis (XRD) confirmed the crystallite size of the host matrix (Si) to be ∼7 nm and also indicated the formation of an additional phase of SiP nano-precipitates after SPS. HR-TEM analysis revealed that the nano-grained network was retained post-sintering with a crystallite size of size of 9 nm and also confirmed the SiP precipitates formation with a size of 4 to 6 nm. As a result, a very low thermal conductivity of ∼2.3W/mK at 900°C has been observed for Si80Ge20 alloy primarily due to scattering of phonons by nanostructured grains and nano-scaled SiP precipitates which further contribute to this scattering mechanism. Electrical conductivity values of SiGe sintered alloy are slightly lower to that of reported values in literature. This was attributed to the formation of SiP which creates a compositional difference between the grain boundary region and the grain region, leading to a chemical potential difference at interface and the grain region. Figure-of-merit (ZT) of n-type Si80Ge20 nanostructured alloy was found to be ≈1.5 at 900°C, which is the highest reported so far at this temperature.

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