Mechanical Crystallization of Metglas Fe78B13Si9 by Cryogenic High Energy Ball Milling

1995 ◽  
Vol 400 ◽  
Author(s):  
B. Huang ◽  
R.J. Perez ◽  
P.J. Crawford ◽  
S.R. Nutt ◽  
E.J. Lavernia

AbstractA nanocrystalline material was synthesized by cryogenic ball milling of Metglas Fe78B13Si9 ribbons. The nanocrystalline structure consisted of α-Fe(Si) and Fe2B grains of 2-13 nm in diameter. In the early stages of milling, bending-induced shear bands were formed, followed by the initial stages of crystallization. As the milling proceeded, predominantly wearlike mechanisms caused further crystallization. The crystallization process was slowed considerably by the addition of 17 at.% Ni during cryogenic milling. The results indicate that the 17 at.% Ni did not form a supersaturated solid solution in the metallic glass, but impeded crystallization by reducing the efficiency of bending and wear-like mechanisms during milling.

1988 ◽  
Vol 132 ◽  
Author(s):  
E. Hellstern ◽  
H. J. Fecht ◽  
C. Garland ◽  
W. L. Johnson ◽  
W. M. Keck

ABSTRACTWe investigated through X- ray diffraction and transmission electron microscopy the crystal refinement of the intermetallic compound AIRu by high- energy ball milling. The deformation process causes a decrease of crystal size to 5–7 rum and an increase of atomic level strain. This deformation is localized in shear bands with a thickness of 0.5 to 1 micron. Within these bands the crystal lattice breaks into small grains with a typical size of 8–14 rum. Further deformation leads to a final nanocrystalline structure with randomly oriented crystallite grains separated by high- angle grain boundaries.


Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1268 ◽  
Author(s):  
Natalia Shkodich ◽  
Alexey Sedegov ◽  
Kirill Kuskov ◽  
Sergey Busurin ◽  
Yury Scheck ◽  
...  

For the first time, a powder of refractory body-centered cubic (bcc) HfTaTiNbZr-based high-entropy alloy (RHEA) was prepared by short-term (90 min) high-energy ball milling (HEBM) followed by spark plasma sintering (SPS) at 1300 °C for 10 min and the resultant bulk material was characterized by XRD and SEM/EDX. The material showed ultra-high Vickers hardness (10.7 GPa) and a density of 9.87 ± 0.18 g/cm³ (98.7%). Our alloy was found to consist of HfZrTiTaNb-based solid solution with bcc structure as a main phase, a hexagonal closest packed (hcp) Hf/Zr-based solid solution, and Me2Fe phases (Me = Hf, Zr) as minor admixtures. Principal elements of the HEA phase were uniformly distributed over the bulk of HfTaTiNbZr-based alloy. Similar alloys synthesized without milling or in the case of low-energy ball milling (LEBM, 10 h) consisted of a bcc HEA and a Hf/Zr-rich hcp solid solution; in this case, the Vickers hardness of such alloys was found to have a value of 6.4 GPa and 5.8 GPa, respectively.


2011 ◽  
Vol 214 (1) ◽  
pp. 117-121 ◽  
Author(s):  
Z. Khakpour ◽  
A.A. Youzbashi ◽  
A. Maghsoudipour ◽  
K. Ahmadi

2017 ◽  
Vol 32 (S1) ◽  
pp. S186-S192 ◽  
Author(s):  
G. Dercz ◽  
I. Matuła ◽  
M. Zubko ◽  
J. Dercz

The study presents the results of the influence of high-energy ball-milling time on the structure of the new β-type Ti–Ta–Nb–Zr alloys for biomedical applications. Initial elemental powders were mechanically alloyed in a planetary high-energy ball mill at different milling times (from 10 to 90 h). Observation of the powder morphology after various stages of milling leads to the conclusion that with the increase of the milling time the size of the powder particles as well as the degree of aggregation change. Clear tendency of crystalline size reduction at every stage of the grinding process is clearly observed. The X-ray diffraction results confirmed the formation of β phase during high-energy ball milling of the precursor mixture of Ti, Ta, Nb, and Zr. The Rietveld refinement method has shown that both the production method and the atomic radii of the elements used in the mechanical synthesis have influence on the structure. Furthermore, it was found that a broadening of the diffraction peaks with increase of the milling time results from an increase in the crystallites dispersion and an enlargement in the lattice distortion. The results indicate that this technique is a powerful and high productive process for preparing new β-titanium alloys with nanocrystalline structure and appropriate morphology.


2010 ◽  
Vol 1267 ◽  
Author(s):  
Kurt Star ◽  
Alex Zevalkink ◽  
Chen-Kuo Huang ◽  
Bruce Dunn ◽  
Jean-Pierre Fleurial

AbstractYb14MnSb11 is a very promising thermoelectric material for high temperature applications. This compound is a member of a large family of Zintl phases with a “14-1-11” A14MPn11 stoichiometry (Pn = P, As, Sb, Bi; A = Ca, Ba, La, Sr, Yb, Eu; M = Mn, Al, Cd, Ga, In, Nb, Zn). Yb14MnSb11 exhibits low lattice thermal conductivity values and a p-type semimetallic behavior with values of the non-dimensional figure of merit zT peaking at 1.4 above 1200 K. There is significant interest in investigating how substitutions on any of the atomic sites impact the charge carrier concentration and mobility, band gap and lattice thermal conductivity. Recent reports have studied substitutions on the Yb and Mn sites with the goal of reducing hole carrier concentration and improving carrier mobility values.High energy ball milling has been shown to be a convenient method of synthesis to prepare Yb14MnSb11 and it has been used here to explore the solid solution systems derived from this compound by substituting Sb with Bi. High energy ball milling is a non-equilibrium process and not all of the 14-1-11 compounds are easily formed with this method. Characterization of the synthesized compositions was done by X-ray diffraction, electron microprobe, and high temperature measurements of the electrical and thermal transport properties up to 1275 K. The experimental results on undoped and doped solid solution samples are compared to that of pure Yb14MnSb11 samples prepared by the same high energy ball milling technique.


2005 ◽  
Vol 392 (1-2) ◽  
pp. 179-183 ◽  
Author(s):  
J.S. Jiang ◽  
X.L. Yang ◽  
L. Gao ◽  
J.K. Guo

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