scholarly journals Mechanically Alloyed Amorphous Ti50(Cu0.45Ni0.55)44–xAlxSi4B2 Alloys with Supercooled Liquid Region

2002 ◽  
Vol 17 (7) ◽  
pp. 1743-1749 ◽  
Author(s):  
L. C. Zhang ◽  
J. Xu ◽  
E. Ma
Keyword(s):  
Amorphous Alloys ◽  
Supercooled Liquid ◽  
High Energy ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
Beneficial Effects ◽  
State Process ◽  
Transmission Electron

A high-energy ball milling procedure has been developed to produce amorphous alloys in Ti50(Cu0.45Ni0.55)44−xAlxSi4B2 (x= 0, 4, 8, 12) powder mixtures. The milling products were characterized using x-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. The Ti-based amorphous alloy powders prepared through this solid-state process exhibit a well-defined glass transition and a supercooled liquid region (ΔTx =64 K) close to the largest achieved so far for Ti-based undercooled melts. The substitution of Al for Cu and Ni has beneficial effects on stabilizing the supercooled liquid. Residual nanocrystals of the αTi structure are uniformly dispersed in the amorphous matrix. The composite alloy powders offer the potential for consolidation in the supercooled liquid region to bulk lightweight amorphous alloys and the possibility to attain desirable mechanical properties.

Amorphization and thermal stability of mechanically alloyed Zr54Cu19Ni8Al8Si5Ti5O1

2005 ◽  
Vol 903 ◽  
Author(s):  
Vassilios Kapaklis ◽  
Athanasios Georgiopoulos ◽  
Peter Schweiss ◽  
Constantin Politis
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Supercooled Liquid ◽  
High Energy ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Thermal Stability Of

AbstractIn the present work we have intentionally introduced significant amount of oxygen to Zr- based alloys. Samples were prepared either by high energy ball milling of the elemental powders and single phase α-ZrO0.43 at the appropriate stoichiometry, or by melting in an Zr-gettered arc melting facility, in both cases under purified argon atmosphere. The effect of small amounts of oxygen (∼1 at. %) on the amorphization process and the thermal stability of mechanically alloyed Zr54Cu19Ni8Al8Si5Ti5O1 powders and arc melted bulk samples was studied by X-ray diffraction and differential scanning calorimetry. It was found that the introduction of oxygen to the alloy composition does not inhibit the amorphization but enhances greatly the thermal stability of the mechanically alloyed amorphous powders. Compared to samples without oxygen prepared either by arc melting or mechanical alloying, samples with oxygen show an increase of the supercooled liquid region from ΔTx−g=Tx−Tg=117 °C to 141 °C where Tx is the crystallization and Tg the glass transition temperature. The glass transition for the mechanically alloyed samples (Tgma) remains unaffected at 336 °C.

PREPARATION AND STRUCTURAL STUDY OF MECHANICAL ALLOYED OF Co50Fe20Cu2V8B20

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 ).

Formation of Amorphous and Nanocrystalline Phases in Mechanically Alloyed Zr-, Al-, and Mg-Base Transition Metal Alloys

1994 ◽  
Vol 362 ◽  
Author(s):  
M. Seidel ◽  
J. Eckert ◽  
H.-D. Bauer ◽  
L. Schultz
Keyword(s):  
Transition Metal ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Metal Alloys ◽  
Liquid Region ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
Transition Metal Alloys ◽  
Base Transition ◽  
Nanocrystalline Phases

AbstractZr-, Al-, and Mg-base transition metal alloys have been prepared by mechanical alloying and investigated by x-ray diffraction, differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). Amorphous phases with significant supercooled liquid region form directly during milling from the crystalline starting materials for Zr- and Mg-base alloys. For Albase alloys the formation of mixtures of amorphous and nanocrystalline phases is observed. The results are compared with data for melt-spun and quenched materials. Possible mechanisms for glass formation and crystallization are discussed.

Superplastic Deformation and Viscous Flow in an Zr-Based Metallic Glass at 410°C

1998 ◽  
Vol 554 ◽  
Author(s):  
T. G. Nieh ◽  
J. G. Wang ◽  
J. Wadsworth ◽  
T. Mukai ◽  
C. T. Liu
Keyword(s):  
Strain Rate ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Single Strain ◽  
Transmission Electron ◽  
Heat Treated ◽  
Different Temperatures

AbstractThe thermal properties of an amorphous alloy (composition in at.%: Zr-10Al-5Ti-17.9Cu-14.6Ni), and particularly the glass transition and crystallization temperature as a function of heating rate, were characterized using Differential Scanning Calorimetry (DSC). X-ray diffraction analyses and Transmission Electron Microscopy were also conducted on samples heat-treated at different temperatures for comparison with the DSC results. Superplasticity in the alloy was studied at 410°C, a temperature within the supercooled liquid region. Both single strain rate and strain rate cycling tests in tension were carried out to investigate the deformation behavior of the alloy in the supercooled liquid region. The experimental results indicated that the alloy did not behave like a Newtonian fluid.

Mechanical Alloying for Preparation of Ti50Fe45Sn5 Amorphous Alloys Powder

2011 ◽  
Vol 480-481 ◽  
pp. 104-108
Author(s):  
Ge Wang ◽  
Chun Zhang ◽  
Yu Ying Zhu ◽  
Zhi Gang Chao ◽  
Qiang Li
Keyword(s):  
Mechanical Alloying ◽  
Amorphous Alloys ◽  
Weight Ratio ◽  
Supercooled Liquid ◽  
High Energy ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Typical Morphology ◽  
Amorphous Powders

Ti50Fe45Sn5 amorphous alloys powder was prepared by mechanical alloying (MA) in a high-energy planetary ball mill. The non-crystallization degree was tested by X-ray diffraction (XRD). It was shown from the XRD results that a higher ball to powder weight ratio (BPR) is advantageous in preparing amorphous alloys powder. The microstructure and shape of the powder was observed by scanning electron microscope (SEM). It was shown from the SEM results that the as-milled amorphous alloys powder is flake shape and assembles together to be agglomeration structure, which is a typical morphology of amorphous powders prepared by MA. Thermodynamic properties and crystallization kinetics behavior of the as-milled amorphous alloys powder were measured by differential scanning calorimeter (DSC). The supercooled liquid region △Tx is broad (up to 119K) and the reduction glass transforming temperature Trg (0.78) is great, which shows that the as-milled amorphous alloys powder has a strong glass-forming ability and the thermal stability of the powder is excellent.

Processing, Characterization and Properties of Specially Constituted Zr-Based Bulk Amorphous Alloys

2010 ◽  
Vol 442 ◽  
pp. 41-51 ◽  
Author(s):  
Muhammad Iqbal ◽  
J.I. Akhter
Keyword(s):  
Amorphous Alloys ◽  
Shear Bands ◽  
Microstructural Characterization ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Liquid Droplets ◽  
Scanning Calorimetry ◽  
Casting Technique ◽  
Stage Crystallization

Bulk metallic glasses (BMGs) are an emerging class of materials. The amorphous alloys have very attractive properties. There is potential for applications. The quaternary and pentanery (ZrCuAlNi)100-xTix (x = 0, 2 and 5 at. %) alloys were synthesized by melting 2-3N pure metals in an arc furnace. Amorphous ingots were produced using Cu mold casting technique. The alloys showed wide supercooled liquid region Tx, high thermal stability and good glass-forming ability (GFA). Many thermal parameters like Trg, , , β and  were measured employing high temperature differential scanning calorimetry (DSC). Structural characterization was carried out by X-ray diffraction (XRD) technique. Microstructural characterization was conducted using high resolution field emission scanning electron microscopy (FESEM) and elemental analysis was done using energy dispersive spectroscopy (EDS). Crystallization behavior and phase formation was studied. Activation energy for crystallization was calculated using Kissinger and Ozawa equations. The alloys show double stage crystallization. Mechanical properties were measured. Compression test was carried out and fracture strength and strain were determined. The fracture behavior was studied which showed veins like patterns, shear bands formation and liquid droplets.

Multicomponent Y-M-Al-Co(M=Ce, Nd or Pr) Amorphous Alloys Developed by Equiatomic Substitution

2012 ◽  
Vol 268-270 ◽  
pp. 301-307 ◽  
Author(s):  
Shi Wen He
Keyword(s):  
Amorphous Alloys ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Size Parameter ◽  
Scanning Calorimetry ◽  
Atomic Size ◽  
Glass Forming ◽  
Electronegativity Difference ◽  
Constituent Elements

Novel multicomponent amorphous alloys have been manufactured by the method of equiatomic substitution for the Y element in Y56Al24Co20 amorphous alloy. Y56-xMxAl24Co20(M=Ce, Pr or Nd; x= 5, 10, 15 and 20at.%) alloys with a diameter of 2 mm have been prepared by suction casting. The glass-forming ability(GFA) was characterized by differential scanning calorimetry(DSC). The supercooled liquid region ∆Tx(=Tx-Tg ) and parameter γ (=Tx/(Tg+Tl)) increase with the increasing of the addition element content. The effects of equiatomic element on ∆Tx of Y56Al24Co20 alloy arise from the increasing of the electronegativity difference Δx, the atomic size parameter δ and the valence electron difference Δn. The results suggest that the GFA of some alloys might be improved by the addition of other equiatomic elements substitution for the alloy constituent elements.

Influence of Al on Quasicrystal Formation in Zr-Ti-Nb-Cu-Ni-Al Metallic Glasses

2003 ◽  
Vol 805 ◽  
Author(s):  
Sergio Scudino ◽  
Jürgen Eckert ◽  
Uta Kühn ◽  
Hergen Breitzke ◽  
Klaus Lüders ◽  
...  
Keyword(s):  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Quasicrystalline Phase ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Al Content ◽  
Transmission Electron ◽  
The Stability ◽  
Thermal Stability Of

ABSTRACTThe effect of Al on the crystallization behavior of (Zr0.616Ti0.087Nb0.027Cu0.15Ni0.12)100–xAlx melt-spun glassy ribbons with x = 7.5, 5, 2.5 and 0 was investigated by differential scanning calorimetry, x-ray diffraction and transmission electron microscopy. The devitrification of the ribbons is characterized by the formation of a metastable quasicrystalline phase during the first stage of the crystallization process even for the alloy with x = 0. Therefore, Al is not essential for quasicrystal formation in the present alloys. However, it affects the properties of the amorphous as well as of the quasicrystalline phase. With decreasing Al content, the temperature range of stability of the quasicrystalline phase increases whereas the thermal stability of the amorphous phase decreases together with a slight decrease of the extension of the supercooled liquid region. Thus, it is concluded that although the addition of Al improves the stability of the glassy phase, it has no beneficial effect on the formation of quasicrystals.

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