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Effects of Ta on Microstructure and Mechanical Property of Ti Zr Cu Pd Ta Alloys

Effects of Ta on Microstructure and Mechanical Property of Ti Zr Cu Pd Ta Alloys

highly dense packed atomic configuration due to low interface energy. Furthermore, the localized deformation mode of the glassy matrix enhances the deformability owing to the softening caused by the increase of temperature in the localized region. Therefore, in this study, higher strength and good plastic deformation were obtained for the 1% Ta- containing alloy. It should be noted that both strength and plastic strain of Ti-Zr-Cu-Pd bulk metallic glasses could also be improved by a proper annealing treatment resulting in 20% nano-crystalline phase precipitation in a previous work. 13)
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Effect of Al on Local Structures of Zr  Ni and Zr  Cu Metallic Glasses

Effect of Al on Local Structures of Zr Ni and Zr Cu Metallic Glasses

characterized by RDF analyses and EXAFS method. Con- trastive effect of Al substitution on the local structure is confirmed in the Zr–Ni and ZrCu metallic glasses. No characteristic change is confirmed in the local structure for the ZrCu metallic glass by substituting Al. In contrast, by substituting Al in the Zr–Ni metallic glass, the coordination number of Zr–Ni decreases clearly, and the for ZrZr increases. These changes would result from the disruption of the strong Zr–Ni correlation and the formation of novel strong correlation of Zr–Al. Al atom would preferentially correlate to Zr atom. As a result, two kind of strong pairs are formed, which leads to the variety of local environment of Zr around Zr. Thus, the Al-induced disordered local environ- ment accompanying with the formation of novel local structure of Zr–Al and decomposition of that of Zr–Ni would improve effectively thermal stability of the Zr–Ni–Al me- tallic glass. In contrast, no significant effect of change in local structure is observed by Al addition in the ZrCu-based metallic glass. We suggest that the Al plays an only topological role for stabilizing the supercooled liquid state.
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Effect of Alloy Composition on Microstructure and Martensitic Transformation Temperature of a Zr-Cu Shape Memory Alloy

Effect of Alloy Composition on Microstructure and Martensitic Transformation Temperature of a Zr-Cu Shape Memory Alloy

The effect of alloy composition on the microstructure of the Zr-Cu system alloys were investigated by XRD. Fig. 2 shows XRD patterns, and it can be seen from the figure that the microstructure of the samples depended on the alloy composition. In particular, the phases of the Zr-Cu binary alloys could be explained in terms of the Zr-Cu equilibrium phase diagram. As shown in Fig. 2 (a)–(c),the dominant phases of the Zr45, Zr50, and Zr55 alloys were ZrCu(M) +Zr 7 Cu 10 , ZrCu(M), and ZrCu(M) + Zr 2 Cu, respectively. In addition, the
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The Electrochemical Hydrogen Sorption Behaviour
of Zr Cu Al Ni Metallic Glasses

The Electrochemical Hydrogen Sorption Behaviour of Zr Cu Al Ni Metallic Glasses

(1) The cathodic polarisation curves of ZrCu–Al–Ni metallic glasses reveal three characteristic potential regions. In the Tafel region, the mechanism of the hydrogen reduc- tion reactions is a fast hydrogen discharge reaction step fol- lowed by a rate-determining electrodic desorption step and the hydrogen absorption reaction is a fast competing step to the electrodic desorption. In the second potential region, the cathodic current density exhibits a plateau and the mechanism is under hydrogen mass transfer control. In the third cathodic potential region, the cathodic current density increases, and
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Formation of Hydroxyapatite on Ti Coated Ti Zr Cu Pd Bulk Metallic Glass

Formation of Hydroxyapatite on Ti Coated Ti Zr Cu Pd Bulk Metallic Glass

Ti-based bulk metallic glasses (BMGs) have an attractive potential to be applied as biomaterials due to their high corrosion resistance, excellent mechanical properties and good biocompatibility. 1) Recently, Ni-free Ti-Zr-Cu-Pd BMGs and their composites with high glass-forming abilities exhibiting high strength and good corrosion resistance have been developed. 2–4) It is well known that the bioactivity of metallic implants are usually evaluated by the nucleation and growth of hydroxyapatite. However, recent results have shown that apatite cannot form directly on an alkali-treated Ti-based BMG. In order to combine the excellent mechanical advantages of Ti-based BMGs with the good bioactivity of pure titanium, the Ti coating is regarded as a possible way to achieve. Sputter-coatings are effective in improving the surface properties of metallic materials, including wear resistance, anti-corrosion proper- ties and oxidation resistance. 5–7) Ti is a good biocompatible
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Characterization of Zr Cu Base Metallic Glasses by means of Hydrogen Internal Friction Peak

Characterization of Zr Cu Base Metallic Glasses by means of Hydrogen Internal Friction Peak

Experimentally, the peak temperature and the peak height of the HIFP in metallic glasses show a decrease and an increase with increasing hydrogen concentration, respectively. 3,4) As the peak height increases to the high-damping region as high as 10 2 the peak temperature in most metallic glasses becomes much lower than room temperature, but the peak temperature in some Zr-Cu base metallic glasses remains near room temperature. Such Zr-Cu base metallic glasses are a potential high-damping and high-strength material, 5–7)

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Hydrogen Internal Friction Peak in Amorphous Zr Cu Al Si Alloys

Hydrogen Internal Friction Peak in Amorphous Zr Cu Al Si Alloys

drogen charged specimen was aged for one day to a few days in the temperature range between 300 K and 330 K to homog- enize the hydrogen distribution in the specimen. The inter- nal friction, Q − 1 , was measured in the temperature range be- tween 80 K and 380 K by means of the vibrating reed method working at about 200 Hz and strain amplitude of 10 − 6 . The internal friction measurements were conducted for all the a- alloy specimens mentioned above in order to pursue the rela- tionship between the anelastic process for the HIFP and the chemical composition of a-alloys. On the other hand, ten- sile tests of a-alloy specimens were made for a-Zr 60 Cu 30 Al 10
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Local Atomic Structure Analysis of Zr Ni and Zr Cu Metallic Glasses Using Electron Diffraction

Local Atomic Structure Analysis of Zr Ni and Zr Cu Metallic Glasses Using Electron Diffraction

order to understand local atomic structures, we next calculated partial-PDFs and performed Voronoi polyhedral analyses for the final structure models. Figure 5 shows partial PDFs for these glasses derived from their structure models together with the total PDFs. A split of the first peak in Zr 66:7 Ni 33:3 is found to be larger than that in Zr 66:7 Cu 33:3 ,

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Deformation Induced Nanoscale Dynamic Transformation Studies in Zr Al Ni Pd and Zr Al Ni Cu Bulk Metallic Glasses

Deformation Induced Nanoscale Dynamic Transformation Studies in Zr Al Ni Pd and Zr Al Ni Cu Bulk Metallic Glasses

It has been reported that crystallization proceeds either via an increase in temperature, which is induced by localized deformations, or a change in the chemical short-range order (CSRO) in the glassy state around the shear bands in the limited condition of a very large permanent strain. 3,10,11) However, little is known about whether crystallization occurs dynamically during a usual inhomogeneous deformation, i.e. the propagation of shear bands in the BMGs with high GFA. Deformation-induced nanocrystallization during quasi-static nanoindentation has been recently reported for Zr-Cu-Ni-Al- Ti BMG. 12) However, a change in the excess free volume
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Development of Ni  and Cu Free Zr Based Bulk Metallic Glasses for Biomedical Applications

Development of Ni and Cu Free Zr Based Bulk Metallic Glasses for Biomedical Applications

Zr-based bulk metallic glasses (BMGs) have continued to attract considerable interest since being discovered in the early 1990s. A number of Zr-based BMGs such as Zr-Al-Ni- Cu, 1) Zr-Ti-Cu-Ni-Be, 2) Zr-Cu-Fe-Al, 3) Zr-Cu-Ni-Al-Ti, 4) and Zr-Al-Co 5) have been developed and reported in the literature. These Zr-based BMGs exhibit a series of superior properties, including high strength, high hardness, relatively low Young’s modulus, large elastic limit and near-net-shape formability, compared to ordinary crystalline alloys. 6) The
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Effect of Processing Scheme on Precipitation Mechanisms and Evolution of Microstructures and Properties of CuAgZr alloy.

Effect of Processing Scheme on Precipitation Mechanisms and Evolution of Microstructures and Properties of CuAgZr alloy.

In 1968, the precipitation mechanisms of Ag precipitates in Cu was studied by Räty and Miekk‐Oja [1]. They investigated the precipitation mechanisms for low stacking fault energy copper alloys, Cu‐5wt%Ag and Cu‐5wt%Ag‐2wt%Al, and found that the precipitates could be easily nucleated in the lattice but the growth would stop at the early stage because of the lack of vacancies. However, stacking faults bounded by Frank partial dislocations were believed to promote the formation of Ag precipitates because the climbing of Frank partials produces vacancies which are needed for the precipitate growth. They concluded that the precipitation process was associated with the growth of extrinsic stacking faults, which resulted in precipitates aligned on the {111} planes. The stacking faults were removed later by retracting partial dislocations. These phenomena could also be observed in some austenitic stainless steel systems [1‐5]. These observations were made by conventional transmission electron microscopy (TEM), and to date, no atomic‐scale observation by high‐resolution TEM has been reported on the precipitation process in CuAgZr alloys.
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Effect of Cold Drawing on Electrical and Mechanical Properties of Cu 5 at% Zr Alloy

Effect of Cold Drawing on Electrical and Mechanical Properties of Cu 5 at% Zr Alloy

similar to the drawing texture of pure Cu. Figure 4 shows the TEM micrographs of cold drawn Cu-5 at% Zr at ¼ 2:2 (a) and 3.6 (b) in the cross section of wire perpendicular to drawing direction. In Figs. 3 and 4, equiaxed microstructures can be observed for both specimens with ¼ 2:2 and 3.6. It is also observed in Fig. 4 that the fiber size decreases with increasing drawing ratio. The SAD patterns in Fig. 4 change from spotty pattern to rather continuous rings with increasing the drawing ratio, corresponding to the change in diffraction patterns at the area parallel to the drawing direction with increasing the drawing ratio as shown in Fig. 3.
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Free Energy Calculations of Crystalline Hard Sphere Complexes Using Density Functional Theory

Free Energy Calculations of Crystalline Hard Sphere Complexes Using Density Functional Theory

However, the Cu 10 Zr 7 structure does not show a minimum in the two-dimensional Gaussian parameter space. The free energy minimum is observed in the liquid limit where α A , α B → 0.0 and rapidly diverges as going away from zero in the two- dimensional Gaussian parameter space. Similar unphysical behavior on the single-component simple cubic (sc) lattice has also been observed recently. 31 Some discrepancies may arise due to the Gaussian parametrization (isotropic) of the density pro fi le. Recent work has focused on the free minimization of the FMT functional with anisotropic density distributions. 42−44 However, a similar anomaly in the bcc hard sphere crystal has been reported. 42 Therefore, we attribute the
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Numerical Studies on Heat Transfer Behavior of Electronics Module with Zr, SiC and Cu Water Based Nanofluids

Numerical Studies on Heat Transfer Behavior of Electronics Module with Zr, SiC and Cu Water Based Nanofluids

From the referred revisions, to the best of author’ awareness, it is understood that there is not a single complete computational study connecting to the influences of water based nanofluids (actually Water-Zr, Water-SiC and Water-Cu) on heat related challenges of electronics modules. With this perspective, the present paper demonstrates numerical investigations with the stated nanofluids on thermal characteristics of electronics modules. And also, the numerical model includes additional key factors like inertia, viscosity and gravity effects apart from the usual issues concerning the present physical problem. However, the stated model ignores both compressibility and viscous heat dissipation effects. The model is very well demonstrated for the detailed numerical investigations on the influences of the already stated nanofluids (as they significantly affect the cooling characteristics) by taking electronics module heat flux and duct inlet nanofluid velocity as the important model parameters. In due course, the model predictions pertaining to the enumerated nanofluids are along the expected lines as well.
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Development of Al Cu Mg Li (Mn,Zr,Sc) alloys for age forming

Development of Al Cu Mg Li (Mn,Zr,Sc) alloys for age forming

Fatigue crack closure is beneficial to fatigue crack growth resistance [7]. Crack closure is enhanced by the presence of shearable precipitates and large grains. An analytical model of roughness induced crack closure has been developed to provide semi-quantitative relation between fatigue crack growth (FCG) and microstructural features [ 8 , 9 ]. As underaged alloys generally show a better FCG resistance, alloy design aims at slowing down the precipitation process in these alloys compared to 2024. This can be achieved by reduced Cu+Mg content and also by microalloying with Li and Zr [1].
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Microstructure and Mechanical Properties of Cu Zr Al Bulk Metallic Glass with Addition of Co

Microstructure and Mechanical Properties of Cu Zr Al Bulk Metallic Glass with Addition of Co

melting a mixture of pure Cu (99.99%), Zr (99.9%), Al (99.99%) and Co (99.99%) under a Ti-gettered argon atmosphere. The ingots were inverted and remelted six times to ensure chemical homogeneity, and then suction cast into water-cooled copper molds to obtain 50 mm long cylindrical rods with a diameter of 2 mm. Thermal analyses concerning crystallization process were performed using a Pyris Diamond differential scanning calorimetry (DSC) at a constant heating rate of 20 K/min under a flow of high- purity argon. Structure of rod sample was examined using a Thermo ARL X-ray diffractometer (XRD) with monochro- matic Cu K¡ radiation and a JEOL JEM-2100F high- resolution transmission electron microscope (HRTEM). The TEM foils were prepared by electrochemical twin-jet polish- ing in a solution of 5 % perchloric acid and 95 % ethanol at 233 K, followed by ion milling with liquid nitrogen cooling. Then the TEM foils were immediately observed under TEM since the thin foils readily oxidize upon exposure to air. Uniaxial compression test was performed on a Sans CMT 5105 testing machine at room temperature under a strain rate of 2 © 10 ¹4 s ¹1 . The test samples were cylinders with a length of 4 mm and a diameter of 2 mm, and the two ends of each sample were polished carefully to ensure parallelism. At least four measurements were conducted for each alloy to obtain reliable results. The fractured samples were examined using a scanning electron microscope (SEM).
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Characteristics of Hypoeutectic Cu Zr Alloy Rods Manufactured by Vertically Upwards Continuous Casting

Characteristics of Hypoeutectic Cu Zr Alloy Rods Manufactured by Vertically Upwards Continuous Casting

structure resulting from the solidification rate, and contribut- able to good wire-drawing ability and the final wire proper- ties. This is because the VUCC method is useful to prevent the semi-solid phase from making micro-shrinkage with its high cooling rate and to possibly prepare the fine dendritic microstructure with resulting a development of the same nanometer-scale fibrous structure as the CMC during wire-drawing. The microstructure of the 15-mm-diameter hy- poeutectic Cu–xZr (x =  0.25–5 at%) alloy rods produced to the pilot-scale manufacturing by the VUCC was investigated and compared with that of the CMC rods. It has become clear that VUCC provided a higher rate of cooling than CMC, with the resulting dendritic microstructure refinement. In addition, the mechanical and electrical properties of the 13.8-μm-di- ameter wire drawn from the VUCC rod were examined, and these results have made it clear that the VUCC is a good po- tential mass-production method of hypoeutectic CuZr al- loys.
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Influence of Overaging on the Superplastic Behavior of an Al Zn Mg Cu Zr Sc Alloy

Influence of Overaging on the Superplastic Behavior of an Al Zn Mg Cu Zr Sc Alloy

The coarse M-phase particles formed during overaging play the most crucial role in the high-temperature tensile tensile deformation of the Al-Zn-Mg-Cu-Zr-Sc alloy. These particles partially melt during high-temperature deformation, which relaxes the stress concentration, assists grain boundary sliding, and endures more cavity coalescences. Coarse M- phase particles also lead to great flow stress reduction and higher strain rate sensitivities. Since no coarse M-phase particle melt during high-temperature tensile deformation in non-overaged specimens, these specimens exhibited less ductility than overaged specimens. This result occurred despite the fact that non-overaged specimens can also maintain their small grain size at high temperature due to the existence of Al 3 (Sc x Zr 1x ) particles effectively retarding
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Exclusive effect of different transition metals supported on wti pillared clay: surface acidity and redox properties

Exclusive effect of different transition metals supported on wti pillared clay: surface acidity and redox properties

concentrations in titanium (0.82M) and in acid (0.2M) were reached by adding water. To prepare the mixed intercalated claywith tungsten and titanium, the W-solution and the Ti- solutionwere simultaneously added drop wise to the suspension of 2 g clay/500 cm 3 water under vigorous stirring at room temperature. The desired percentage of tungsten added to the clay is 10%and the Ti/clay ratio equals10 mmol/g clay. After 24 h stirring, the solid fraction was separated by centrifugation and filtration, and then it was washed several times with distilled water and dried at room temperature. In the next step the transition metal in aqueous solution (2%) was introduced into the intercalated clay, by incipient wetness impregnation method, under stirring at room temperature.The transition metal (Mo, Cu, Mn, Ce, V, Co, Zr) sources areammonium heptamolybdatetetrahydrate, copper (II) chloride, manganese (II) chloride, cerium (III) chloride, ammonia vanadate, cobalt (II) chloride and zirconium (IV) chloride, respectively. Finally, all the samples are calcined at 500°C at a heating rate of 2°C min -1 for 3h under air flow. The samples are referenced as TM/WTi-PILC in which TM = Mo, Cu, Mn, Ce, V, Co, Zr and WTi-PILC is the support.
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Cu–Zr Thin Film Electrodeposited from an Aqueous Solution Using Rectangular Pulse Current Over a Megahertz Frequency Range

Cu–Zr Thin Film Electrodeposited from an Aqueous Solution Using Rectangular Pulse Current Over a Megahertz Frequency Range

The Zr electrodeposition from the aqueous solution greater than or equal to the mole ratio =1.73 was identified. The Zr content in the Cu-Zr film at the resonant frequency of the rectangular pulse current indicated a maximal value. The resonant frequency interval between the neighboring resonant frequencies was approximately 0.26 MHz on average. The XRD analysis showed that the CuZr thin film had an FCC structure that includes Zr atoms as substitutional atoms. The Zr content slightly decreases with the amplitude of the rectangular pulse current. SEM images of the CuZr thin films indicated the aggregation of islands that appeared like cauliflowers consisting of nano-scale grains.
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