An anomalous X-ray structural study of an amorphous La55Al25Ni20 alloy with a wide supercooled liquid region

The influence of annealing on the structural changes and the mechanical properties of Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit-1) bulk metallic glass was systematically studied by varying the annealing times at 703 K. The evolution of the structural state at a relatively high temperature within the supercooled liquid region was studied by thermal analysis, x-ray diffraction, high-resolution transmission electron microscopy, extended x-ray absorption fine structure, and dilatometric measurements. The deformation behavior and the mechanical properties were also examined by carrying out hardness and compression tests for the specimens annealed for various times.

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Formation of Ni57Zr20Ti22Pb1 Amorphous Powders by Mechanical Alloying

Materials Science Forum ◽

10.4028/www.scientific.net/msf.539-543.2767 ◽

2007 ◽

Vol 539-543 ◽

pp. 2767-2772

Author(s):

Pee Yew Lee ◽

S.S. Hung ◽

Jason S.C. Jang ◽

Giin Shan Chen

Keyword(s):

Thermal Stability ◽

Supercooled Liquid ◽

Supercooled Liquid Region ◽

Liquid Region ◽

X Ray Diffraction ◽

Mechanically Alloyed ◽

Atomic Size ◽

X Ray ◽

Amorphous Powders ◽

Thermal Stability Of

In the current study, the amorphization behavior of mechanically alloyed Ni57Zr20Ti22Pb1 powder was examined in details. The conventional X-ray diffraction results confirm that the fully amorphous powders formed after 5 hours of milling. The thermal stability of the Ni57Zr20Ti22Pb1 amorphous powders was investigated by differential scanning calorimeter (DSC). As the results demonstrated, the glass transition temperature (Tg) and the crystallization temperature (Tx) are 760 K and 850 K, respectively. The supercooled liquid region is 90 K. The appearance of wide supercooled liquid region may be mainly due to the Pb additions which cause the increasing differences in atomic size of mechanically alloyed Ni57Zr20Ti22Pb1 powders.

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Glass Forming Ability in Amorphous Ti50Cu35-xNi15Snx Alloys Prepared by Mechanical Alloying

Materials Science Forum ◽

10.4028/www.scientific.net/msf.475-479.3451 ◽

2005 ◽

Vol 475-479 ◽

pp. 3451-3458 ◽

Cited By ~ 5

Author(s):

Chung Kwei Lin ◽

C.C. Hsu ◽

R.R. Jeng ◽

Y.L. Lin ◽

C.H. Yeh ◽

...

Keyword(s):

Mechanical Alloying ◽

Differential Scanning Calorimeter ◽

Supercooled Liquid ◽

Supercooled Liquid Region ◽

Liquid Region ◽

X Ray Diffraction ◽

X Ray ◽

Glass Forming ◽

Amorphous Powders ◽

X Ray Absorption

in the present study, amorphous ti50cu35-xni15snx (x=0~7) alloy powders were synthesized by mechanical alloying technique. the amorphization behavior of ti50cu28ni15sn7 alloy powders was examined in details by scanning electron microscopy, differential scanning calorimeter, x-ray diffraction, and synchrotron x-ray absorption spectroscopy. the results show that fully amorphous powders formed after 7 hours of milling. The thermal stability of the Ti50Cu35-xNi15Snx amorphous powders was investigated by differential scanning calorimeter. The amorphous Ti50Cu35Ni15 powders (i.e., x=0) exhibit no glass transition behavior. However, the amorphous Ti50Cu35-xNi15Snx (x=3~7) powders were found to exhibit a supercooled liquid region before crystallization. Amorphous Ti50Cu28Ni15Sn7 alloy powders exhibits a wide supercooled liquid region of 61 K.

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Crystallization of Cu60Ti20Zr20 metallic glass with and without pressure

Journal of Materials Research ◽

10.1557/jmr.2003.0123 ◽

2003 ◽

Vol 18 (4) ◽

pp. 895-898 ◽

Cited By ~ 30

Author(s):

J. Z. Jiang ◽

B. Yang ◽

K. Saksl ◽

H. Franz ◽

N. Pryds

Keyword(s):

Metallic Glass ◽

Crystalline Phase ◽

Supercooled Liquid ◽

Supercooled Liquid Region ◽

Lattice Parameters ◽

Type Structure ◽

Liquid Region ◽

X Ray Diffraction ◽

X Ray ◽

Residual Amorphous Phase

Structural stability of a Cu60Ti20Zr20 metallic glass under pressure up to 4.5 GPa was investigated by x-ray diffraction. The sample exhibited a supercooled liquid region of 33 K and a ratio of the glass-transition temperature to the liquidus temperature of 0.63. The glass crystallized in two-step transformation processes in the pressure range of 0–4.5 GPa; the first was a primary reaction to form a Cu51Zr14-type structure crystalline phase with a spacing group P6/m (175) and lattice parameters a=11.235 Å and c=8.271 Å, and then the residual amorphous phase crystallized into a MgZn2-type structure crystalline phase with a spacing group P63/mmc (194) and lattice parameters a=5.105 Å and c=8.231 Å. Both crystallization temperatures increased with pressure having a slope of 19 K/GPa. The increase of the first crystallization temperature with increasing pressure in the glass can be explained by the suppression of atomic mobility. No significant structural change was detected in the Cu60Ti20Zr20 glass annealed in vacuum at 697 K for 1 h as compared to the as-prepared sample from x-ray diffraction measurements.

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PREPARATION AND STRUCTURAL STUDY OF MECHANICAL ALLOYED OF Co50Fe20Cu2V8B20

International Journal of Modern Physics B ◽

10.1142/s0217979205031687 ◽

2005 ◽

Vol 19 (15n17) ◽

pp. 2775-2779

Author(s):

X. F. ZHANG ◽

X. Q. HUANG ◽

R. W. PENG ◽

G. Q. WANG ◽

S. Y. ZHANG

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Amorphous Alloys ◽

Supercooled Liquid ◽

Supercooled Liquid Region ◽

Liquid Region ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Transmission Electron

The amorphous alloys of Co 50 Fe 20 Cu 2 V 8 B 20 are successfully obtained by using the mechanical alloying technique. The sample is analyzed by X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. The DSC result of the powder sample milled for 120 h shows a complete amorphous phase and a wide supercooled liquid region (Tx - Tg ≃ 80 K ).

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Quenched-in Free Volume Vf, Deformation-induced Free Volume, the Glass Transition Tg and Thermal Expansion in glassy ZrNbCuNiAl measured by Time-resolved Diffraction in Transmission

MRS Proceedings ◽

10.1557/proc-806-mm3.5 ◽

2003 ◽

Vol 806 ◽

Cited By ~ 3

Author(s):

A. R. Yavari ◽

M. Tonegaru ◽

N. Lupu ◽

A Inoue ◽

E. Matsubara ◽

...

Keyword(s):

Heat Treatment ◽

Glass Transition ◽

Free Volume ◽

Supercooled Liquid ◽

Supercooled Liquid Region ◽

Liquid Region ◽

Time Resolved ◽

X Ray ◽

Excess Free Volume ◽

Rapidly Solidified

ABSTRACTUsing high-precision X-ray dilatometry, we have succeeded in directly measuring excess quenched-in free-volume Vf in metallic glasses. The method was applied to the very easy glass forming Zr57Nb5Cu15.4Ni12.6Al10 (Vit 106). The annealing out of the order of 0.5% free volume was observed during heat treatment of rapidly solidified glassy ribbons. Excess free volume was also generated by heavy deformation and observed to anneal out during heat treatment. Once the excess free volume anneals out, the glass transition Tg appears clearly as a break in the x-ray dilatation curves as the glass goes over to the supercooled liquid region prior to crystallization at Tx.

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Bulk Mg-Cu-Y-Al Alloys in the Amorphous, Supercooled Liquid and Crystalline States

MRS Proceedings ◽

10.1557/proc-644-l4.1 ◽

2000 ◽

Vol 644 ◽

Cited By ~ 1

Author(s):

S. Linderoth ◽

N. Pryds ◽

M. Eldrup ◽

A.S. Pedersen ◽

M. Ohnuma ◽

...

Keyword(s):

Control Volume ◽

Supercooled Liquid ◽

Supercooled Liquid Region ◽

External Pressure ◽

Al Alloys ◽

Liquid Region ◽

X Ray Diffraction ◽

X Ray ◽

Prepared State ◽

History Of

AbstractBulk Mg-Cu-Y-Al alloys, prepared by casting into a wedge-shaped copper mold, have been studied in the as-prepared, the supercooled liquid, and the crystalline states. In the as-prepared state x-ray diffraction of sub-millimeter sized regions were performed using a focused x-ray beam. The phase composition of the cross section as well as of the surface of the wedge-shaped specimen was investigated as a function of position. The cooling history of the alloy was experimentally determined and compared to results of a control-volume finite-difference modelling study. The experimentally determined and the calculated cooling rates were correlated with the observed amorphous/crystalline structure. The transition from an amorphous to a crystalline state was followed by x-ray diffraction studies as a function of time at specific temperatures in the region between the glass transition and the crystallization temperature. Based on these results a temperature-time-phase diagram was constructed. The dependence of external pressure on the crystallisation temperature was investigated by in situ high-temperature and high- pressure x-ray powder diffraction by using synchrotron radiation. The investigations form the basis for a selection of the optimum temperature in the supercooled liquid region for performing deformation/shaping of the Mg-based alloys.

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Redox-structure dependence of molten iron oxides

Communications Materials ◽

10.1038/s43246-020-00080-4 ◽

2020 ◽

Vol 1 (1) ◽

Author(s):

Caijuan Shi ◽

Oliver L. G. Alderman ◽

Anthony Tamalonis ◽

Richard Weber ◽

Jinglin You ◽

...

Keyword(s):

Iron Oxides ◽

Structure Refinement ◽

Supercooled Liquid ◽

Supercooled Liquid Region ◽

Distribution Functions ◽

Liquid Region ◽

X Ray ◽

Reducing Conditions ◽

Wide Range ◽

Potential Structure

Abstract The atomic structural arrangements of liquid iron oxides affect the thermophysical and thermodynamic properties associated with the steelmaking process and magma flows. Here, the structures of stable and supercooled iron oxide melts have been investigated as a function of oxygen fugacity and temperature, using x-ray diffraction and aerodynamic levitation with laser heating. Total x-ray structure factors and their corresponding pair distribution functions were measured for temperatures ranging from 1973 K in the stable melt, to 1573 K in the deeply supercooled liquid region, over a wide range of oxygen partial pressures. Empirical potential structure refinement yields average Fe–O coordination numbers ranging from ~4.5 to ~5 over the region FeO to Fe2O3, significantly lower than most existing reports. Ferric iron is dominated by FeO4, FeO5 and FeO6 units in the oxygen rich melt. For ferrous iron under reducing conditions FeO4 and FeO5 units dominate, in stark contrast to crystalline FeO.

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