Metallic Glass Surface Patterning by Micro-Molding

2005 ◽  
Author(s):  
Jeffrey Bardt ◽  
Nathan Mauntler ◽  
Gerald Bourne ◽  
Tony L. Schmitz ◽  
John C. Ziegert ◽  
...  
Keyword(s):  
Glass Transition ◽  
Metallic Glass ◽  
Glass Surface ◽  
Surface Patterning ◽  
Spatial Proximity ◽  
Two Dimensional ◽  
Deep Reactive Ion Etching ◽  
Metallic Material ◽  
Aspect Ratios ◽  
Micro Molding

The micro-molding of bulk amorphous metal to create sub-micrometer to sub-millimeter surface features was investigated. The goal was to demonstrate the reproduction of such features in a metallic material from a master. The bulk metallic glass material was embossed between the glass transition and crystallization temperatures. Silicon wafers patterned by deep reactive ion etching were used as masters. The patterns were designed to test the effects and interactions of aspect ratios, geometry, and spatial proximity. In addition to these patterns, a master was developed to mold two-dimensional channel geometries. Comparisons between the replicated features and the molds are provided.

METGLAS ALLOY 2826

Alloy Digest ◽  
1976 ◽  
Vol 25 (11) ◽  
Keyword(s):  
Magnetic Properties ◽  
Metallic Glass ◽  
Liquid State ◽  
Single Phase ◽  
Heat Treating ◽  
High Permeability ◽  
Metallic Material ◽  
Nickel Iron ◽  
Rapid Quench ◽  
Chemical Corporation

Abstract METGLAS Alloy 2826 (Fe40Ni40P14B6) is a ferromagnetic, high permeability, nickel-iron metallic glass which, when appropriately annealed, yields a material similar to the higher nickel containing permalloys in magnetic properties. Alloy 2826 is a single phase, opaque metallic material with a glass-like structure obtained by a very rapid quench from the liquid state. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on forming and heat treating. Filing Code: Ni-235. Producer or source: Allied Chemical Corporation.

Fast mobility induced self-lubrication at metallic glass surface

2021 ◽  
Vol 129 (16) ◽  
pp. 165303
Author(s):  
Yumiao Lu ◽  
Xiaodi Liu ◽  
Baoan Sun ◽  
Chengrong Cao ◽  
Mingxiang Pan ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Glass Surface

scholarly journals Effects of Annealing on Enthalpy Recovery and Nanomechanical Behaviors of a La-Based Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 579
Author(s):  
Ting Shi ◽  
Lanping Huang ◽  
Song Li
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Structural Relaxation ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Nanoindentation Measurement

Structural relaxation and nanomechanical behaviors of La65Al14Ni5Co5Cu9.2Ag1.8 bulk metallic glass (BMG) with a low glass transition temperature during annealing have been investigated by calorimetry and nanoindentation measurement. The enthalpy release of this metallic glass is deduced by annealing near glass transition. When annealed below glass transition temperature for 5 min, the recovered enthalpy increases with annealing temperature and reaches the maximum value at 403 K. After annealed in supercooled liquid region, the recovered enthalpy obviously decreases. For a given annealing at 393 K, the relaxation behaviors of La-based BMG can be well described by the Kohlrausch-Williams-Watts (KWW) function. The hardness, Young’s modulus, and serrated flow are sensitive to structural relaxation of this metallic glass, which can be well explained by the theory of solid-like region and liquid-like region. The decrease of ductility and the enhancement of homogeneity can be ascribed to the transformation from liquid-like region into solid-like region and the reduction of the shear transition zone (STZ).

TEM study of bubble formation in Ti–Ta–Si–Ni metallic glass surface alloy on TiNi SMA substrate during additive thin-film electron-beam synthesis

Vacuum ◽  
2021 ◽  
pp. 110597
Author(s):  
V.P. Rotshtein ◽  
V.O. Semin ◽  
S.N. Meisner ◽  
L.L. Meisner ◽  
F.A. D'yachenko ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Beam ◽  
Metallic Glass ◽  
Glass Surface ◽  
Bubble Formation ◽  
Surface Alloy

Observation of the Pinning-Induced Crystal-Hexatic-Glass Transition in Two-Dimensional Colloidal Suspensions

2021 ◽  
Vol 38 (10) ◽  
pp. 106101
Author(s):  
Xiaoyan Sun ◽  
Huaguang Wang ◽  
Hao Feng ◽  
Zexin Zhang ◽  
Yuqiang Ma
Keyword(s):  
Glass Transition ◽  
Colloidal Suspensions ◽  
Two Dimensional ◽  
Colloidal Systems ◽  
Fundamental Understanding ◽  
New Strategy ◽  
Glassy Materials ◽  
Colloidal Glass ◽  
Orientational Correlation

Identification of the glass formation process in various conditions is of importance for fundamental understanding of the mechanism of glass transitions as well as for developments and applications of glassy materials. We investigate the role of pinning in driving the transformation of crystal into glass in two-dimensional colloidal suspensions of monodisperse microspheres. The pinning is produced by immobilizing a fraction of microspheres on the substrate of sample cells where the mobile microspheres sediment. Structurally, the crystal-hexatic-glass transition occurs with increasing the number fraction of pinning ρ pinning, and the orientational correlation exhibits a change from quasi-long-range to short-range order at ρ pinning = 0.02. Interestingly, the dynamics shows a non-monotonic change with increasing the fraction of pinning. This is due to the competition between the disorder that enhances the dynamics and the pinning that hinders the particle motions. Our work highlights the important role of the pinning on the colloidal glass transition, which not only provides a new strategy to prevent crystallization forming glass, but also is helpful for understanding of the vitrification in colloidal systems.

scholarly journals CFD Analysis of Urban Canopy Flows Employing the V2F Model: Impact of Different Aspect Ratios and Relative Heights

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Fabio Nardecchia ◽  
Annalisa Di Bernardino ◽  
Francesca Pagliaro ◽  
Paolo Monti ◽  
Giovanni Leuzzi ◽  
...  
Keyword(s):  
Flow Field ◽  
Water Channel ◽  
Flow Regimes ◽  
Two Dimensional ◽  
Mean Flow ◽  
Ansys Fluent ◽  
Practical Applications ◽  
Aspect Ratios ◽  
Starting Point ◽  
Step Down

Computational fluid dynamics (CFD) is currently used in the environmental field to simulate flow and dispersion of pollutants around buildings. However, the closure assumptions of the turbulence usually employed in CFD codes are not always physically based and adequate for all the flow regimes relating to practical applications. The starting point of this work is the performance assessment of the V2F (i.e., v2¯ − f) model implemented in Ansys Fluent for simulating the flow field in an idealized array of two-dimensional canyons. The V2F model has been used in the past to predict low-speed and wall-bounded flows, but it has never been used to simulate airflows in urban street canyons. The numerical results are validated against experimental data collected in the water channel and compared with other turbulence models incorporated in Ansys Fluent (i.e., variations of both k-ε and k-ω models and the Reynolds stress model). The results show that the V2F model provides the best prediction of the flow field for two flow regimes commonly found in urban canopies. The V2F model is also employed to quantify the air-exchange rate (ACH) for a series of two-dimensional building arrangements, such as step-up and step-down configurations, having different aspect ratios and relative heights of the buildings. The results show a clear dependence of the ACH on the latter two parameters and highlight the role played by the turbulence in the exchange of air mass, particularly important for the step-down configurations, when the ventilation associated with the mean flow is generally poor.

Crystal to Glass Transition and Melting in Two Dimensions

1993 ◽  
Vol 321 ◽  
Author(s):  
M. Li ◽  
W. L. Johnson ◽  
W. A. Goddard
Keyword(s):  
Glass Transition ◽  
Intermediate Phase ◽  
Orientational Order ◽  
Finite Size ◽  
Two Dimensions ◽  
Size Difference ◽  
Two Dimensional ◽  
Atomic Size ◽  
Bond Orientational Order ◽  
Dynamics Simulations

ABSTRACTThermodynamic properties, structures, defects and their configurations of a two-dimensional Lennard-Jones (LJ) system are investigated close to crystal to glass transition (CGT) via molecular dynamics simulations. The CGT is achieved by saturating the LJ binary arrays below glass transition temperature with one type of the atoms which has different atomic size from that of the host atoms. It was found that for a given atomic size difference larger than a critical value, the CGT proceeds with increasing solute concentrations in three stages, each of which is characterized by distinct behaviors of translational and bond-orientational order correlation functions. An intermediate phase which has a quasi-long range orientational order but short range translational order has been found to exist prior to the formation of the amorphous phase. The destabilization of crystallinity is observed to be directly related to defects. We examine these results in the context of two dimensional (2D) melting theory. Finite size effects on these results, in particular on the intermediate phase formation, are discussed.

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