Phase Equilibria in the Zr-Cu-Al System: Implications for Bulk Metallic Glass Formation

1998 ◽  
Vol 554 ◽  
Author(s):  
S. A. Syed ◽  
D. Swenson
Keyword(s):  
Ternary Phase ◽  
Amorphous State ◽  
Bulk Amorphous Alloy ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Forming ◽  
Equilibrium Relationships ◽  
Equilibrium Phases ◽  
Preliminary Phase

AbstractPreliminary phase equilibrium relationships have been established in the Zr-Cu-Al system at 800 °C, using a combination of X-ray diffraction and electron probe microanalysis. These results are similar to previous investigations that have been reported in the literature. Several ternary phases are found to exist in this system, many of which lie within the gross compositional vicinity of interest to bulk amorphous alloy formation. The equilibrium phases present in the alloy Zr65Cu27.5A17.5, which exhibits a particularly high Tx-Tg in the amorphous state, are Zr2Cu and minor amounts of two additional phases: Zr3Al and what may be a ternary phase with a composition near Zr6CuAl3. When the 800 °C phase diagram isotherm is correlated with the known glass forming composition range of the Zr-Cu-Al system, it is found that the best glass forming behavior is confined to those regions of the diagram in which all equilibria include Zr-Cu constituent binary phases and Al-poor ternary phases. This may suggest that difficulties in the nucleation of these binary phases plays a role in the glass forming ability of Zr-Cu-Al and related higher order alloys.

Processing and Properties of Amorphous Magnesium-Based Eco-Materials

2011 ◽  
Vol 695 ◽  
pp. 186-189 ◽  
Author(s):  
X. L. Fu ◽  
Ming Jen Tan ◽  
Anders W.E. Jarfors ◽  
Manoj Gupta
Keyword(s):  
Magnesium Alloys ◽  
Amorphous State ◽  
Tensile Tests ◽  
Transportation Industry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Forming ◽  
Total Failure ◽  
High Temperature Tensile ◽  
Room Temperature Strength

Magnesium alloys are the lightest known structural material and have been very attractive for usage in marine and transportation industry (for its weight savings and payload increase), and also for its portability in hand-held devices. It is recyclable and one of the most abundant metal. Lately, it has gained attention for its biocompatibility, and also its biodegradable properties depending on the alloying elements. They can be used as a biomaterial in various applications from heart stents to implant screws and fixtures. In this work, amorphous magnesium alloys have been processed, based on its glass forming ability, by various techniques in order to obtain its amorphous state, and the microstructure are characterized by thermal analysis, X-ray diffraction and electron microscopy. Their mechanical properties are also presented. High temperature tensile tests show similar strength to room temperature strength, while the total failure strain is significantly increased from around 0.5% to 10%.

Structure of Ni-B-Melts by Means of X-Ray Diffraction

1983 ◽  
Vol 38 (10) ◽  
pp. 1098-1102
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
B. Sedelmeyer ◽  
S. Steeb
Keyword(s):  
Metallic Glass ◽  
Structure Factor ◽  
Amorphous State ◽  
Rapid Quenching ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Forming ◽  
Melt Spin ◽  
Total Structure Factor ◽  
Total Structure

Abstract The structural results for molten Ni81B19 are compared with the structure of a metallic glass which can be obtained at the same composition by rapid quenching the melt within a melt spin equipment. Structural relationship exists between the molten and the amorphous state. This feature follows especially from a marked asymmetry of the second maximum of the structure factor obtained from the melts, to which corresponds the splitting up of the second maximum in the total structure factor of the amorphous specimen. With the Ni53B47- and the Ni43B57 -melts which don't belong to the concentration range of glass-forming Ni-B-melts no peculiarities in the range of the second maximum of the structure factor were observed.

W-Doped TiO2 Preparation and Photocatalytic Degradation of Guaiacol

2014 ◽  
Vol 513-517 ◽  
pp. 33-36 ◽  
Author(s):  
Zi Chang Xie ◽  
Ying Wang ◽  
Peng Wang ◽  
Lei Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Degradation Rate ◽  
Amorphous State ◽  
X Ray Diffraction ◽  
Model Compounds ◽  
Plant Fibers ◽  
X Ray ◽  
Crystallite Structure

In this paper, W-doped TiO2 (W-TiO2) powder was prepared in hydrothermal method by mixing TiO2 and ammonium metatungstate. The catalysts were characterized by X-ray diffraction and ultraviolet spectrophotometer. The results displayed that W-TiO2 showed an anatase crystallite structure with 2 % W content. W-element in W-TiO2 was amorphous state. The guaiacol was degraded with the W-TiO2 in the visible light. It was a model compounds of lignin existed in the plant fibers. The degradation rate of guaiacol was increased with the photocatalytic time, as high as 88.21 % after 360 min irradiation. It was concluded that the W-TiO2 had an obvious photocatalytic activity under visible light. It can be used in the photocatalytic degradation of lignin.

scholarly journals Supplementary X-ray studies of the Ni-Sn-Bi system

2007 ◽  
Vol 43 (2) ◽  
pp. 141-150 ◽  
Author(s):  
G.P. Vassilev ◽  
K.I. Lilova ◽  
J.C. Gachon
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Phase Equilibria ◽  
Ternary Compound ◽  
Approximate Formula ◽  
Ternary Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Peaks ◽  
Scanning Electron

Phase equilibria were studied in the system Ni-Sn-Bi. Special attention has been paid to the identification of the recently found ternary phase. For this purpose samples were synthesized using intimately mixed powders. After annealing and quenching, all alloys were analyzed by scanning electron microscope and by X-ray diffraction. The results give evidences about the existence of a ternary compound with approximate formula Ni6Sn2Bi to Ni7Sn2Bi. Overlapping of some neighboring diffraction peaks of this phase with NiBi and Ni3Sn_LT is the reason for the difficulties related to the X-ray diffraction identification of the ternary phase.

scholarly journals Влияние режима получения образцов и термообработки на локальную структуру халькогенидного полупроводника Ge-=SUB=-2-=/SUB=-Sb-=SUB=-2-=/SUB=-Te-=SUB=-5-=/SUB=-

2022 ◽  
Vol 56 (3) ◽  
pp. 291
Author(s):  
С.Н. Гарибова ◽  
А.И. Исаев ◽  
С.И. Мехтиева ◽  
С.У. Атаева ◽  
Р.И. Алекперов
Keyword(s):  
Heat Treatment ◽  
Thermal Processing ◽  
Thermal Evaporation ◽  
Amorphous State ◽  
Hexagonal Structure ◽  
Structural Elements ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Matrix ◽  
Close Range

Specifics of "amorphous state - crystal" phase transitions in dependence on the samples obtaining method and thermal processing, as well as changes in the structure and close range order in the arrangement of the atoms of Ge20Sb20.5Te51 chalcogenide semiconductors have been studied by the x-ray diffraction and Raman spectroscopy. It has been shown that Ge20Sb20.5Te51 films obtained by thermal evaporation on an unheated substrate are amorphous; after heat treatment at 220 and 400 °C, transform into a crystalline phase with a cubic and hexagonal structure. The chemical bonds and the main structural elements that form the matrix of the investigated objects, as well as the changes that occur in them during heat treatment, have been determined.

scholarly journals Characterization of the Interface Between the Bulk Glass Forming Alloy Zr41Ti14Cu12Ni10Be23 with Pure Metals and Ceramics

2000 ◽  
Vol 15 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
Jan Schroers ◽  
Konrad Samwer ◽  
Frigyes Szuecs ◽  
William L. Johnson
Keyword(s):  
Sessile Drop ◽  
Bulk Glass ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Glass Forming ◽  
Processing Times ◽  
Thermal Stability Of

The reaction of the bulk glass forming alloy Zr41Ti14Cu12Ni10Be23 (Vit 1) with W, Ta, Mo, AlN, Al2O3, Si, graphite, and amorphous carbon was investigated. Vit 1 samples were melted and subsequently solidified after different processing times on discs of the different materials. Sessile drop examinations of the macroscopic wetting of Vit 1 on the discs as a function of temperature were carried out in situ with a digital optical camera. The reactions at the interfaces between the Vit 1 sample and the different disc materials were investigated with an electron microprobe. The structure and thermal stability of the processed Vit 1 samples were examined by x-ray diffraction and differential scanning calorimetry. The results are discussed in terms of possible applications for composite materials.

Investigation of Amorphous/Crystalline State in Cu-Hf-Al Alloys

2010 ◽  
Vol 649 ◽  
pp. 87-92
Author(s):  
E. Nagy ◽  
Viktória Rontó ◽  
Jenő Sólyom ◽  
András Roósz
Keyword(s):  
Amorphous Alloys ◽  
Great Influence ◽  
Amorphous State ◽  
High Strength ◽  
Al Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Different Shapes ◽  
Important Purpose

Cu-Hf-Al alloys are considered to be relatively new ones among Cu-based bulk amorphous alloys. Cu-Hf-Al alloys have high strength in amorphous state and this property makes many applications feasible for the industry. During the production of amorphous alloys the most important purpose is to produce them in the biggest diameter to make them suitable for a wide range of applications. The circumstances of the production process have a great influence on the developing structure. In the present work solidification of Cu-Hf-Al alloys were investigated. The alloys were cast into different shapes with different Al contents with special regard to the appearance of the amorphous/crystalline structure. The appearance and the structure of crystalline phases were determined by X-ray diffraction and X-ray, DSC and metallographic measurements were used to investigate the developing structure.

Hydrogen and Oxygen Chemisorptions and Titrations by Platinum on Zirconia Catalysts Reduced between 673 and 1273 K

1985 ◽  
Vol 2 (2) ◽  
pp. 55-68 ◽  
Author(s):  
L. Tournayan ◽  
A. Auroux ◽  
H. Charcosset ◽  
R. Szymanski
Keyword(s):  
Surface Composition ◽  
Pt Catalyst ◽  
Hydrogen Chemisorption ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Chemisorption ◽  
Alloy Particles ◽  
Frontal Method ◽  
The Mean

Some 10 wt % Pt supported on zirconia catalysts were investigated by hydrogen and oxygen chemisorptions and titrations by means of automated catharometric equipment (frontal method). Microcalorimetry was further used to determine the heats of oxygen chemisorption. The temperature of reduction by hydrogen, TR, was varied between 673 and 1273 K. At 673 K, the H and O coverages of Pt were about the same as for Pt supported on SiO2 (Euro Pt catalyst). The increase in TR from 673 to 873 K was accompanied by a strong decrease of the hydrogen to oxygen chemisorption ratio. It is proposed that this is due to Pt1– xZr x alloy formation, with small values of x (≤0·05). When TR was above 873 K, x determined by X-ray diffraction analysis increased up to 0·25. The hydrogen chemisorption is confined to Pt s, while the oxygen chemisorption takes place on Pt s and Zr sO x. The surface composition may be derived and is found twice as rich in Zr as the mean composition of the alloy particles.

X-ray diffraction studies of vivianite, metavivianite, and barićite

1985 ◽  
Vol 49 (350) ◽  
pp. 81-85 ◽  
Author(s):  
T. Sameshima ◽  
G. S. Henderson ◽  
P. M. Black ◽  
K. A. Rodgers
Keyword(s):  
Monoclinic Phase ◽  
Amorphous State ◽  
Twin Plane ◽  
Coarse Grained ◽  
X Ray Diffraction ◽  
X Ray ◽  
Triclinic Phase ◽  
Type Lattice ◽  
Relationship Of ◽  
The Relationship

AbstractVivianite specimens from various world localities yield X-ray powder patterns of two types: one corresponds with that shown by synthetic Fe3(PO4)2· 8H2O and is not readily distinguished from that of barićite; the second shows reflections of monoclinic vivianite and triclinic metavivianite along with reflections of a bobierrite-type phase. The triclinic phase occurs as two twin-related lattices with twin plane 110 being the structural equivalent of 010 in the monoclinic phase. The relationship of the bobierrite-type lattice to the other two has not been established. The ternary pattern is produced by some coarse-grained vivianites on natural oxidation. Finer grained vivianites oxidise to an X-ray amorphous state without passing through a triclinic intermediate.

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