scholarly journals Thermoplastic Forming of a Hydrophilic Surface with a Nanostructure Array on Zr-Cu-Ni-Al-Y Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1520
Author(s):  
Sirui Cheng ◽  
Jiang Ma ◽  
Feng Gong ◽  
Jun Shen
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Low Cost ◽  
Supercooled Liquid ◽  
Volume Density ◽  
Roughness Coefficient ◽  
Limiting Factor ◽  
Nanostructure Fabrication ◽  
Thermoplastic Forming ◽  
Large Roughness

The poor thermoplastic formability of reactive Zr-based bulk metallic glass becomes the main limiting factor for replacing the noble-metal-based and Be-rich bulk metallic glasses in nanostructure fabrication. In our work, a (Zr50.7Cu28Ni9Al12.3)98.5Y1.5 bulk metallic glass with good thermoplastic formability has been developed by alloying, where Y addition enlarges the processing window and decreases the viscous resistance of supercooled liquid caused by the high free volume density. The prepared Zr-Cu-Ni-Al-Y bulk metallic glass nanostructure retains the amorphous characteristic and generates the complex oxidization products in the surface layer. The enhanced hydrophilicity of the as-embossed surface follows a Wenzel-impregnating wetting regime, and it can be attributed to the large roughness coefficient induced by the capillary effect. This study provides a low-cost and environmentally friendly bulk metallic glass system to manufacture the nanostructure with a broad prospect in the field of electrocatalysis.

The Redistribution and Alignment of Crystalline Flakes in a Bulk Metallic Glass Composite during Thermoplastic Forming

2011 ◽  
Vol 702-703 ◽  
pp. 971-974
Author(s):  
Wan Qiang Xu ◽  
Lalu Robin ◽  
Kevin J. Laws ◽  
Rong Kun Zheng ◽  
Michael Ferry
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Amorphous Matrix ◽  
Volume Fraction ◽  
Supercooled Liquid ◽  
Glass Composite ◽  
Uniform Dispersion ◽  
Thermoplastic Forming ◽  
Bulk Metallic Glass Composite

An In-situ Mg-based bulk metallic glass (BMG) composite containing 40% volume fraction of Mg-rich crystalline flakes was produced by die casting. During cooling from the melt, the flakes nucleate heterogeneously and subsequently grow with their broad faces parallel to the {0001} plane. This generated a uniform dispersion of randomly-oriented flakes within an amorphous matrix. When compressed uniaxially up to 60% reduction in the supercooled liquid (SCL) region, the flakes in this composite were substantially aligned their broad faces towards the compression plane that generated a strong //ND fibre texture.

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).

Strong Liquid Behavior of Zr-Ti-Cu-Ni-Be Bulk Metallic Glass Forming Alloys

1996 ◽  
Vol 455 ◽  
Author(s):  
Ralf Busch ◽  
Andreas Masuhr ◽  
Eric Bakke ◽  
William L. Johnson
Keyword(s):  
Glass Transition ◽  
Melting Point ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Supercooled Liquid ◽  
Glass Transition Region ◽  
Glass Forming ◽  
Liquid Behavior ◽  
Metallic Liquids ◽  
Microscopic Origin

ABSTRACTThe viscosities of the Zr46.75Ti8.25Cu7.5Ni10Be27.5 and the Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass forming liquids was determined from the melting point down to the glass transition in the entire temperature range of the supercooled liquid. The temperature dependence of the viscosity in the supercooled liquid obeys the Vogel-Fulcher-Tammann (VFT) relation. The fragility index D is about 20 for both alloys and the ratio between glass transition temperature and VFT temperature is found to be 1.5. A comparison with other glass forming systems shows that these bulk metallic glass formers are strong liquids comparable to sodium silicate glass. Furthermore, they are the strongest among metallic glass forming liquids. This behavior is a main contributing factor to the glass forming ability since it implicates a higher viscosity from the melting point down to the glass transition compared to other metallic liquids. Thus, the kinetics in the supercooled liquid is sluggish and yields a low critical cooling rate for glass formation. The relaxation behavior in the glass transition region of the alloys is consistent with their strong glassy nature as reflected by a stretching exponent that is close to 0.8. The microscopic origin of the strong liquid behavior of bulk metallic glass formers is discussed.

The oxidation behavior of a novel Ni-free Zr–Cu-based bulk metallic glass composite in the supercooled liquid and crystallization states

2014 ◽  
Vol 53 ◽  
pp. 34-39 ◽  
Author(s):  
Huei-Sen Wang ◽  
Wei-Hau Li ◽  
Mei-Hui Wu ◽  
Hou-Guang Chen ◽  
Jason Shian-Ching Jang ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Oxidation Behavior ◽  
Supercooled Liquid ◽  
Glass Composite ◽  
Bulk Metallic Glass Composite

An Auto-Regressive Exogenous-Based Temperature Controller for a Hybrid Thermoplastic Microforming of Surgical Blades From Bulk Metallic Glass

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Nattasit Dancholvichit ◽  
Shiv Kapoor
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Temperature Control ◽  
Pid Controller ◽  
Proportional Integral Derivative ◽  
Forming Process ◽  
Steady State Temperature ◽  
Blade Edge ◽  
Thermoplastic Forming ◽  
Auto Regressive

Abstract Temperature control is critical in manufacturing of the multifacet bulk metallic glass (BMG) knife edge. The temperature control in thermoplastic forming process could make a significant effect on the type of deformation, which ultimately results in the final blade edge shape. The controller selection is based on the knowledge of the model from system identification, the performance of the controllers, and the feasibility of the implementation to the testbed. In this study, temperature control, using fuzzy logic, is implemented along with auto-regressive exogenous, ARX model, which can maintain the steady-state temperature within the range of ±2.5 K. With this proposed controller, experiments have shown similar or better results of multifacet blade geometries than those manufactured using proportional–integral–derivative (PID) controller. The blade edge samples are successfully manufactured with the average straightness and the edge radius of the blade of 3.66 ± 0.5 μm and 25.7 ± 6 nm, respectively.

Nanoscale Molding of a Zirconium Based Bulk Metallic Glass

2007 ◽  
Author(s):  
Kavic Rason ◽  
Brad Kinsey
Keyword(s):  
Aspect Ratio ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
High Aspect Ratio ◽  
Supercooled Liquid ◽  
Mold Material ◽  
Molding Process ◽  
Silicon Mold ◽  
Interfacial Energies ◽  
A Value

Geometrically complex, high aspect ratio microstructures and limited aspect ratio nanostructures have been successfully fabricated in supercooled Bulk Metallic Glass (BMG) substrates by molding against patterned Silicon and Silicon dioxide substrates. However, demand exists for similar metallic substrates with high aspect ratio, nanoscale features. Van Der Waals based interfacial energies between the supercooled liquid BMG and the Silicon cavity represent a substantial obstacle to the direct scaling of the molding process to the nanoscale. In an effort to investigate these effects, experiments were conducted using molds of various compositions: Silicon, SiO2 and SiO2 coated with Gold. The Gold coating failed to impact molding performance due to the thin layer deposited. However, drastically superior results were obtained by using a Silicon mold because of the variation in interfacial interaction between the BMG and the mold material. In addition, a theoretical model to predict achievable aspect ratio is presented and was found to be in qualitative agreement with experimental results. Finally, a value for the surface tension of Viterloy-1b within it’s supercooled liquid state was deduced from experimental data.

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