Bulk Metallic Glasses (bulk + metallic_glasses)

Distribution by Scientific Domains
Polymers and Materials Science81%

Selected Abstracts

Statistic Analysis of the Mechanical Behavior of Bulk Metallic Glasses,

ADVANCED ENGINEERING MATERIALS, Issue 5 2009
Hai Bin Yu
The Weibull distribution is used to characterize the mechanical behavior of a bulk metallic glass (BMG). The strength of the BMG is quite stable, while the plasticity is much less stable. The reason is attributed to the fraction and distribution of free volumes, which are sensitive to processing conditions. The results demonstrate the close relationship between the distribution and fraction of free volumes and plasticity in BMGs. [source]

Designing Ductile Zr-Based Bulk Metallic Glasses with Phase Separated Microstructure,

ADVANCED ENGINEERING MATERIALS, Issue 5 2009
Xinghao Du
Using the thermodynamic computation, the phase-separated Zr-based bulk metallic glasses with a enhanced plasticity up to 20% are developed. The as-cast microstructure is characterized by the macroscopic heterogeneities consisting of the phase-separated regions and glassy matrix regions. The microscaled phase-separated feature is the cause of the remarkable plasticity, and the homogeneous and concurrent formation of multiple shear bands is crucial for the plasticity improvement in metallic glasses. [source]

Bulk Metallic Glasses with Functional Physical Properties (Adv. Mater.

ADVANCED MATERIALS, Issue 45 2009
45/2009)
[source]

Bulk Metallic Glasses with Functional Physical Properties

ADVANCED MATERIALS, Issue 45 2009
W. H. Wang
Abstract In this review, we report on the formation of a variety of novel, metallic, glassy materials that might well have applications as functional materials. The metallic glasses, with excellent glass-forming ability, display many fascinating properties and features such as excellent wave-absorption ability, exceptionally low glass-transition temperatures (,35,60,°C) approaching room temperature, ultralow elastic moduli comparable to that of human bone, high elasticity and high strength, superplasticity and polymer-like thermoplastic formability near room temperature, an excellent magnetocaloric effect, hard magnetism and tunable magnetic properties, heavy-fermion behavior, superhydrophobicity and superoleophobicity, and polyamorphism, all of which are of interest not only for basic research but also for technological applications. A strategy based on elastic-moduli correlations for fabrication of bulk metallic glasses (BMGs) with controllable properties is presented. The work has implications in the search for novel metallic glasses with unique functional properties, for advancing our understanding of the nature and formation of glasses, and for extending the applications of the materials. [source]

Metallic Glasses: Nanoscale Solute Partitioning in Bulk Metallic Glasses (Adv. Mater.

ADVANCED MATERIALS, Issue 3 2009
3/2009)
Devitrification of bulk metallic glass leads to novel microstructures with high-density nanoscale crystalline precipitates evenly distributed in a glassy matrix. Xun-Li Wang and co-workers report on p. 305 that significant chemical segregation is revealed in unprecedented detail by atom-probe tomography. This level of detail is crucial for understanding the interference peaks observed in small-angle X-ray and neutron scattering experiments. [source]

Nanoscale Solute Partitioning in Bulk Metallic Glasses,

ADVANCED MATERIALS, Issue 3 2009
Ling Yang
Devitrification of bulk metallic glass leads to a novel microstructure, with high-density nanoscale crystalline precipitates evenly distributed in a glassy matrix. Significant chemical segregation is revealed at unprecedented detail by atom-probe tomography. This level of detail is crucial for understanding the interference peaks observed in small-angle X-ray and neutron scattering experiments, an unsolved mistery for over a decade. [source]

Designing Ductile Zr-Based Bulk Metallic Glasses with Phase Separated Microstructure,

ADVANCED ENGINEERING MATERIALS, Issue 5 2009
Xinghao Du
Using the thermodynamic computation, the phase-separated Zr-based bulk metallic glasses with a enhanced plasticity up to 20% are developed. The as-cast microstructure is characterized by the macroscopic heterogeneities consisting of the phase-separated regions and glassy matrix regions. The microscaled phase-separated feature is the cause of the remarkable plasticity, and the homogeneous and concurrent formation of multiple shear bands is crucial for the plasticity improvement in metallic glasses. [source]

Back Cover: TMS Bulk-Metallic Glasses Symposium V (Adv. Eng.

ADVANCED ENGINEERING MATERIALS, Issue 11 2008
Mater.
The backcover shows the nanoindentation of a Zr-based bulk metallic glass with an Al-concentration of 13 at%. Around the indent shear bands are observed indicating some plasticity of that glass. More about the glass-forming ability and ductility of Zr-based and Al-rich bulk metallic glasses can be found in the paper by R. Wunderlich et al. on page 1020. [source]

Bulk Metallic Glasses with Functional Physical Properties

ADVANCED MATERIALS, Issue 45 2009
W. H. Wang
Abstract In this review, we report on the formation of a variety of novel, metallic, glassy materials that might well have applications as functional materials. The metallic glasses, with excellent glass-forming ability, display many fascinating properties and features such as excellent wave-absorption ability, exceptionally low glass-transition temperatures (,35,60,°C) approaching room temperature, ultralow elastic moduli comparable to that of human bone, high elasticity and high strength, superplasticity and polymer-like thermoplastic formability near room temperature, an excellent magnetocaloric effect, hard magnetism and tunable magnetic properties, heavy-fermion behavior, superhydrophobicity and superoleophobicity, and polyamorphism, all of which are of interest not only for basic research but also for technological applications. A strategy based on elastic-moduli correlations for fabrication of bulk metallic glasses (BMGs) with controllable properties is presented. The work has implications in the search for novel metallic glasses with unique functional properties, for advancing our understanding of the nature and formation of glasses, and for extending the applications of the materials. [source]

Precursory microstructures in Zr,Cu,Al,Ni bulk metallic glasses examined by anomalous small-angle scattering at the Zr K edge

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2007
Isao Murase
Anomalous small-angle X-ray scattering measurements of Zr,Cu,Al,Ni quaternary alloys have been made at the Zr K absorption edge. In melt-quenched samples, small cluster components without crystallization were found. The contrast change at the edge suggested that compositional fluctuation of Al is incorporated. [source]

Glass forming ability and nanocrystallization kinetics of Fe65Nb10B25 metallic glasses

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2010
J. Torrens-Serra
Abstract In this work the mechanisms controlling the nanocrystallization kinetics of the Fe65Nb10B25 metallic glasses have been determined by the combination of the analysis microstructural data from XRD and TEM, and the kinetic analysis performed using the Master Curve method of the continuous heating and isothermal calorimetric curves. The results show that the transformation starts by the nucleation and interface controlled growth of the Fe23B6 -type phase that changes to diffusion controlled growth as the transformation advances until is stopped by the soft-impingement effect. The transformation is modeled in the framework of the Kolmogorov,Johnson,Mehl,Avrami (KJMA) theory using constant activation energy expressions for the nucleation frequency and interface-controlled growth and taking into account the reduction of those quantities with the transformed fraction due to the change in the matrix composition using a mean-field approximation. The parameters of the modeling are determined from the coupling between the isothermal and constant heating rate calorimetric analysis and from the quantitative analysis of microstructural data. This is the outset for the determination of the viscosity, driving force for crystallization, and interfacial energy when replacing the constant activation energy expressions by the classical nucleation and growth ones. Both the glass forming ability in Fe,Nb,B based bulk metallic glasses and the temperature dependence of the interfacial energy are discussed in terms of the influence of the minor alloying elements. [source]