Amorphous Alloy (amorphous + alloy)

Distribution by Scientific Domains


Selected Abstracts


Nanocrystallized Al92Sm8 Amorphous Alloy Investigated by High-Resolution Microscopy and 3D Atom-Probe Analysis

ADVANCED ENGINEERING MATERIALS, Issue 3 2007
T. Gloriant
A partially nanocrystallized amorphous Al92Sm8 (at.%) alloy was obtained directly by rapid solidification (one-step method). Because of the significant retained plasticity of the as-quenched alloy, the nanostructure and the atomic species distribution within the nanocomposite material could be characterized by field-ion microscopy (FIM) and by three-dimensional atom-probe analysis (3DAP). [source]


Air-Oxidation of a Cu45Zr45Al5Ag5 Bulk Metallic Glass,

ADVANCED ENGINEERING MATERIALS, Issue 5 2009
Wu Kai
This work studied the oxidation behavior of a Ag-containing Cu,Zr,Al-based amorphous alloy (CZA4-BMG) in dry air at 375,500,C. The oxidation kinetics of CZA4-BMG obeyed a multi-stage parabolic-rate law, and its steady-state oxidation-rate constants were slightly lower than those of Ag-free amorphous alloy (CZA3-BMG) at the temperature below 450,C, indicating that the addition of Ag played a partly blocking effect in reducing the available cross-sections of the substrate, which in turn reduced inward diffusion of oxygen, thereby leading to the reduction of oxidation rates for CZA4-BMG. [source]


Annealed crystallization of ultrafine amorphous NiB alloy studied by XAFS

JOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001
Shiqiang Wei
XAFS has been used to investigate the local structure evolutions of ultrafine amorphous NiB alloy during the annealed crystal-lization process. A nanocrystalline Ni phase with the local structure of crystalline Ni-like and a crystalline Ni3B, have been produced for ultrafine amorphous NiB alloy under the annealed temperature of 573 K. The results rule out Rojo et al.'s devitrification mechanism of Ni80B20 amorphous alloy in which they considered that an amorphous pure Ni phase is formed in the first exothermic process. However, our results are almost identical with Riveiro et al.'s conclusion in which the intermediate state is interpreted as two metastable crystalline phases of Ni3B and Ni-rich NiB alloy. With the annealed temperature going onto 773 K, the ultrafine NiB sample is further decomposed and crystallized into crystalline Ni with long-range order. [source]


Influence of Nb substituted for Fe on the microstructure and magnetic properties of Fe-based nanocomposite alloy

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 12 2007
N. Q. Hoa
Abstract The influence of Nb substituted for Fe on the microstructure and magnetic properties including the magnetoimpedance effect of a Fe-based have been investigated. The nanocomposite structure composed of ultra-fine Fe(Si) grains embedded in an amorphous matrix was obtained by annealing the Fe-based amorphous alloy prepared by rapidly-quenched method. The measurements of thermomagnetic curves indicated that the Curie temperature of the amorphous phase of the samples decreases with increasing Nb content. The optimal heat treatment was performed at Ta = 480 C for 30 min and showed that the ultrasoft magnetic properties of nanocomposite materials were obtained. The magnetoimpedance (MI) of these samples has been studied in range frequency from 1MHz to 5 MHz and varying a dc magnetic field within 300 Oe. The correlation between the MI effect and the soft magnetic properties is discussed. The incremental permeability ratio (PR) showed the drastic changes of soft magnetic properties as a function of annealing temperatures. ( 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Engraving of a Pd77.5Cu6Si16.5 Bulk Metallic Glass,

ADVANCED ENGINEERING MATERIALS, Issue 6 2007
G. Fiore
A bulk cylinder, 2 mm in diameter, of Pd77.5Cu6Si16.5 amorphous alloys has been obtained by copper moulding. Slices of the sample have been engraved in the undercooled liquid regime just above the glass transition reproducing details of a 5 Euro cent coin by suitably choosing the annealing procedure. The samples remained glassy after processing. [source]


Bulk Metallic Glass Composites with Transformation-Mediated Work-Hardening and Ductility

ADVANCED MATERIALS, Issue 25 2010
Yuan Wu
A bulk metallic glass (BMG) composite with large tensile ductility and work-hardening capability (see figure) was developed by applying the "transformation-induced plasticity" concept to amorphous alloys. The current approach is not believed to be limited to the current BMG composite but could promote ductility in other BMG systems, offering a new paradigm for developing BMGs with improved ductility as practical engineering materials. [source]


Magnetic properties of Fe76X2B22 (X=Cr,Zr,Nb) amorphous alloys

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003
A. Chrobak
Abstract The paper contains experimental results referring to optimization of soft magnetic properties and crystallization in the Fe76X2B22 (X=Cr,Zr,Nb) amorphous alloys. We have used measurement of thermomagnetic balance, magnetic permeability, coercive field and also HREM and X-ray diffraction techniques. It was shown that Zr and Nb alloying additions cause a slowing down of diffusion processes and an increase of the annealing for 1 hour optimization temperature of about 50 and 100 K, respectively. Activation enthalpies of the crystallization process were determined as: 2.0 eV (X=Cr), 2.6 eV (X=Zr) and 4.4 eV (X=Nb). [source]