Glass Formation By Mechanical Alloying

1986 ◽  
Vol 80 ◽  
Author(s):  
L. Schultz ◽  
E. Hellstern
Keyword(s):  
Solid State ◽  
Mechanical Alloying ◽  
Solid State Reaction ◽  
Structural Similarity ◽  
Enthalpy Of Mixing ◽  
High Energy ◽  
High Coercivity ◽  
Superconducting Transition ◽  
Mechanically Alloyed ◽  
Glass Forming

AbstractAmorphous metallic powders can be formed by mechanical alloying in a high-energy ball mill. Starting from the elemental, crystalline powders, ball milling first produces powder particles with a characteristically layered microstructure. Further milling leads to an ultrafine composite in which amorphization by solid state reaction takes place. The glass-forming range has been determined in detail for Fe-Zr and Ni-Zr. In Fe-Zr it differs completely from rapidly quenched amorphous samples. A systematic study of alloys of 3d transition metals with Zr and Ti shows that the glass-forming ability depends critically on a large negative free enthalpy of mixing. The results lead to the conclusion that amorphization by mechanical alloying is based on a solid state reaction and occurs under a metastable thermodynamic equilibrium neglecting the existence of intermetallic phases. Measurements of the superconducting transition temperature and Möβbauer studies show the structural similarity of mechanically alloyed and rapidly quenched amorphous samples. Finally mechanical alloying of FeZrB and NdFeB is described. Whereas FeZrB becomes amorphous after an additional annealing, a microcrystalline powder with very high coercivity is formed for NdFeB.

Progress of solid-state reaction during mechanical alloying of Zr-Al-Cu-Ni bulk metallic glass-forming alloys

1997 ◽  
Vol 226-228 ◽  
pp. 383-387 ◽  
Author(s):  
M. Seidel ◽  
M. Reibold ◽  
I. Bächer ◽  
H.-D. Bauer ◽  
J. Eckert ◽  
...  
Keyword(s):  
Solid State ◽  
Metallic Glass ◽  
Mechanical Alloying ◽  
Bulk Metallic Glass ◽  
Solid State Reaction ◽  
Glass Forming

Mechanical solid state reaction for synthesis of β–SiC powders

1995 ◽  
Vol 10 (3) ◽  
pp. 659-667 ◽  
Author(s):  
M. Sherif El-Eskandarany ◽  
Kenji Sumiyama ◽  
Kenji Suzuki
Keyword(s):  
Solid State ◽  
Mechanical Alloying ◽  
Solid State Reaction ◽  
Gas Flow ◽  
Elevated Temperatures ◽  
High Energy ◽  
Lattice Parameter ◽  
Morphological Properties ◽  
Phonon Modes ◽  
Uniform Size

Stoichiometric β-SiC powders have been successfully prepared by solid state reaction of elemental silicon and carbon powders via the mechanical alloying process. The mechanical alloying process was performed in a high-energy ball mill under argon gas flow at room temperature. The solid-state reacted alloy powders have been characterized as a function of the milling time by means of x-ray diffraction, infrared absorption, scanning and transmission electron microscopy, and chemical analysis. Complete fcc-SiC (β-phase) alloy powders were obtained after 1080 ks of continuous milling. The lattice parameter (a0) of the formed β-SiC was calculated to be 0.4357 nm. No free silicon and/or carbon crystals were observed. The existence of transverse optical (TO) and longitudinal optical (LO)-like phonon modes is observed for the end-product alloy powders. Mechanically alloyed β-SiC powders are stable at elevated temperatures (1773 K) and did not transform to any other phases. The end-product β-SiC alloy powders possess excellent morphological properties, such as homogeneous shape (spherical morphology) with fine and smooth surface relief and uniform size (less than 0.5 μm in diameter). The fabricated β-SiC alloy powders have fine cell-like structure with nanoscale dimensions of about 7 nm.

Phase Transformation and Synthesis of Ni Substituted CoSb3 Skutterudite Synthesis during Solid State Reaction

2005 ◽  
Vol 475-479 ◽  
pp. 857-860 ◽  
Author(s):  
Jun You Yang ◽  
Yuehua Chen ◽  
Jiangying Peng ◽  
Wen Zhu ◽  
Xin Li Song
Keyword(s):  
Phase Transformation ◽  
Solid State ◽  
Mechanical Alloying ◽  
Solid State Reaction ◽  
Ball Mill ◽  
Single Phase ◽  
Lattice Parameter ◽  
Maximum Solubility ◽  
Mechanically Alloyed ◽  
Skutterudite Compound

Starting from elemental Co (99.9%), Ni (99.9%) and Sb (99.99%) powders, Co4-xNixSb12 powder mixture with different Ni concentration were subjected to mechanical alloying by using a planetary ball mill. Phase transformation during mechanical alloying process of Co-Ni-Sb system was studied in this paper. Ni substituted skutterudite could be synthesized by solid state reaction. With assistance of hot pressing for two hours, the as mechanically alloyed low Ni concentration powders could be completely transformed into skutterudite compound. The lattice parameter of Ni substituted skutterudite compound complies well with Vegard law when x is not more than 0.2. When Ni concentration is larger than the maximum solubility, NiSb2 compound forms and single phase skutterudite compound can not be obtained.

Preparation and Identification of Barium Monoferrite by Solid State Reaction Method

2019 ◽  
Vol 34 ◽  
pp. 46-52
Author(s):  
Iulian Ştefan ◽  
Gabriel Benga ◽  
Ionel Dănuț Savu ◽  
Sorin Vasile Savu ◽  
Adrian Olei
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Mechanical Alloying ◽  
Solid State Reaction ◽  
Barium Carbonate ◽  
Solid State Reaction Method ◽  
High Energy ◽  
Phase Identification ◽  
Formation Temperature ◽  
Reaction Method

In this paper, BaFe2O4 was prepared from BaCO3 and Fe2O3 powders through the solid state reaction method. This method starts by mixing the barium carbonate and iron oxide in order to homogenize the raw materials and takes place in a wet medium. For a better homogenization of BaCO3 and Fe2O3 powders and in order to reduce the monoferrite formation temperature, it was used the mechanical alloying process for 3 and 9 hours in a high energy ball mill. Particle size distributions of the milled powders were analyzed by a BROOKHAVEN 90PLUS device. To understand the phase formation temperature, thermogravimetry analysis was carried out. The phase identification of the calcined powder was carried out by D8 Discover Bruker X-ray diffractometer. The results showed that once with the reduction of powders particle size, in the mechanical alloying process, the temperature of the solid state reaction of barium monoferrite was also reduced.

Synthesis and Characterization of Nanosized NiAl Particles

1998 ◽  
Vol 520 ◽  
Author(s):  
T. Chen ◽  
J.M. Hampikian
Keyword(s):  
Solid State ◽  
Mechanical Alloying ◽  
Long Range ◽  
Solid State Reaction ◽  
Shear Bands ◽  
Range Order ◽  
Long Range Order ◽  
Mechanically Alloyed ◽  
Edge Dislocations

ABSTRACTNanophase NiAl powders were synthesized by solid state reaction via ball milling of elemental Ni and Al powders under an argon atmosphere for 0-8 h, 16 h, 24 h, and 48 h. Structural characterization of the nanophase NiAI was performed by x-ray diffraction and transmission electron microscopy. The oxidation behavior of the powders was studied by thermogravimetric analysis. It was found that the Ni + Al = NiAl solid state reaction took place between 4 and 5 hours of mechanical alloying. After 5 h or more of mechanical alloying, the phase of the ball milled particles was the B2 structure, with average grain sizes which decreased with increasing mechanical alloying times. The relationship between the long-range-order parameters and mechanical alloying time was studied. After 5 h, 6 h, 8 h, 16 h, 24 h, and 48 h mechanical alloying, the long-range-order parameter was determined to be approximately 0.82, 0.75, 0.75, 0.75, 0.71, and 0.63, respectively. Iron contamination was observed, resulting from wear of the steel vial and balls. In the mechanically alloyed NiAl nanoparticles, edge dislocations, shear bands, subgrains, distorted regions, and a large number of grain boundaries were observed.

GLASS FORMATION IN MECHANICALLY ALLOYED Fe-BASED SYSTEMS

2009 ◽  
Vol 02 (04) ◽  
pp. 147-155 ◽  
Author(s):  
C. SURYANARAYANA ◽  
SATYAJEET SHARMA
Keyword(s):  
Solid State ◽  
Mechanical Alloying ◽  
Glass Formation ◽  
Glassy State ◽  
Mechanically Alloyed ◽  
Lattice Contraction ◽  
Processing Methods ◽  
Glass Forming ◽  
State Processing ◽  
Alloy Systems

Rapid solidification processing of metallic melts has been traditionally employed to synthesize metallic glasses in several alloy systems. However, in recent years, solid-state processing methods, and more specifically, mechanical alloying, have become popular methods to synthesize glassy phases in metallic alloy systems. Although a large number of criteria have been developed to identify alloy compositions that can be solidified into the glassy state, very few attempts have been made to predict the glass-forming ability by solid-state processing methods. To evaluate if some clear criteria could be developed to predict glass formation by solid-state processing methods and to understand the mechanism of glass formation, mechanical alloying of powder blends was conducted on several Fe -based alloy systems. Three different aspects of glass formation are specifically discussed in this paper. One is the development of a criterion for identifying glass-forming systems from phase diagram features, the second is the process of mechanical crystallization (formation of a crystalline phase on continued milling of the amorphous powders obtained by mechanical alloying), and the third is the novel phenomenon of lattice contraction during amorphization. It was shown that the conditions under which a glassy phase is formed by mechanical alloying are different from the solidification methods.

scholarly journals Effect of Milling Parameters on the Development of a Nanostructured FCC–TiNb15Mn Alloy via High-Energy Ball Milling

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1225
Author(s):  
Cristina García-Garrido ◽  
Ranier Sepúlveda Sepúlveda Ferrer ◽  
Christopher Salvo ◽  
Lucía García-Domínguez ◽  
Luis Pérez-Pozo ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Ball Mill ◽  
Milling Time ◽  
High Energy ◽  
Planetary Mill ◽  
Nominal Composition ◽  
Mechanically Alloyed ◽  
Milling Parameters ◽  
Energy Ball ◽  
Full Conversion

In this work, a blend of Ti, Nb, and Mn powders, with a nominal composition of 15 wt.% of Mn, and balanced Ti and Nb wt.%, was selected to be mechanically alloyed by the following two alternative high-energy milling devices: a vibratory 8000D mixer/mill® and a PM400 Retsch® planetary ball mill. Two ball-to-powder ratio (BPR) conditions (10:1 and 20:1) were applied, to study the evolution of the synthesized phases under each of the two mechanical alloying conditions. The main findings observed include the following: (1) the sequence conversion evolved from raw elements to a transitory bcc-TiNbMn alloy, and subsequently to an fcc-TiNb15Mn alloy, independent of the milling conditions; (2) the total full conversion to the fcc-TiNb15Mn alloy was only reached by the planetary mill at a minimum of 12 h of milling time, for either of the BPR employed; (3) the planetary mill produced a non-negligible Fe contamination from the milling media, when the highest BPR and milling time were applied; and (4) the final fcc-TiNb15Mn alloy synthesized presents a nanocrystalline nature and a partial degree of amorphization.

Luminescent Properties of LiTaO3:Tm3+, Yb3+ Phosphors Prepared by Ball Milling Method

2013 ◽  
Vol 423-426 ◽  
pp. 426-429
Author(s):  
Xin Ze Wang ◽  
Zhong Xin Liu ◽  
Hong Jian Gao ◽  
Yani Jing ◽  
Chang Lin Li ◽  
...  
Keyword(s):  
Solid State ◽  
Ball Milling ◽  
Solid State Reaction ◽  
Blue Emission ◽  
Photoluminescence Property ◽  
Luminescent Properties ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Conventional Solid State Reaction ◽  
Energy Ball

LiTaO3: Tm3+, Yb3+powders were synthesized by a high-energy ball-milling (HEB) method compared with the conventional solid-state reaction (SSR) method. Under the excitation of 980 nm laser, the strong blue emission (477 nm) band is observed and attributed to1G4-3H6of Tm3+. Because of it causing high local temperature and narrow particles size, increasing the contact area between the particles and improved crystallinity of the host, synthesis by high-energy ball milling show higher photoluminescence (PL) intensity compared to the solid state reaction method. In the process of mechanical milling, Tm3+, Yb3+co-doped LiTaO3phosphors with high photoluminescence property could be achieved at a relatively low reaction temperature.

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