Fracture Toughness Study on Zr-based Bulk Metallic Glasses

2007 ◽  
Vol 1048 ◽  
Author(s):  
Jin-yoo Suh ◽  
Mary Laura Lind ◽  
C. Paul Kim ◽  
R. Dale Conner ◽  
William L Johnson
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Fracture Surfaces ◽  
Linear Elastic ◽  
Elastic Fracture

AbstractThe fracture toughness of Zr-based bulk metallic glasses of various compositions was studied in the as-cast and annealed condition. Properties were characterized using x-ray and differential scanning calorimetry (DSC) and fracture surfaces were examined using electron microscopy (SEM). Quaternary Zr-Ti-Cu-Be alloys consistently had linear elastic fracture toughness values greater than 80 MPa·m1/2, while Vitreloy 1, a Zr-Ti-Cu-Ni-Be alloy, had an average fracture toughness of 48.5 MPa·m1/2 with a large amount of scatter. The addition of iron to Vitreloy 1 reduced the fracture toughness to 25 MPa·m1/2. Fracture surfaces were carefully analyzed using electron microscopy. Some samples had highly jagged patterns at the beginning stage of crack propagation, and the roughness of this jagged pattern correlated well with the measured fracture toughness values. These jagged patterns, the main source of energy dissipation in the sample, were attributed to the formation of shear bands inside the sample. The Zr-Ti-Cu-Be alloy, having KQ=85 MPa·m1/2 as cast, was annealed at various time/temperature combinations. When the alloy was annealed 50°C below Tg, the fracture toughness dropped to 6 MPa·m1/2, while DSC and X-ray showed the alloy to still be amorphous. The roughness of the fracture surfaces on relaxed samples also compared well with the relative fracture toughness.

scholarly journals Studi Metode Pendinginan Super Cepat untuk Pembentukan Bulk Metallic Glasses pada Paduan Cu45Zr45Al5Ag5

2019 ◽  
Vol 3 (2) ◽  
pp. 10-17
Author(s):  
Andromeda Dwi Laksono ◽  
Rifqi Aulia Tanjung
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Metallic Glasses ◽  
Electron Probe ◽  
Bulk Metallic Glasses ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Energy Dispersion Spectrometer ◽  
Scanning Electron

Bulk Metallic Glass (BMG) memiliki sifat mekanik, magnetik, kimia dan fisik yang berbeda dengan paduan polikristalin karena susunan internal atomnya yang tidak teratur. Sehingga, BMG memiliki kekuatan mekanik yang baik, kekerasan yang tinggi, ketahanan terhadap aus dan korosi yang tinggi, dan kehalusan permukaan yang baik. Berdasarkan sifat tersebut, BMG memiliki kelayakan yang menjanjikan di bidang industry. Dalam penelitian ini, metode pengecoran cetakan di tembaga digunakan untuk menyiapkan BMG paduan Cu45Zr45Al5Ag5. Paduan dileburkan ulang dengan pendinginan super cepat menggunakan mesin pendingin di bawah temperatur -25 oC. Dengan metode pengecoran cetakan di tembaga, sampel ukuran besar berbentuk batang dipotong dengan diameter 2 mm hingga 4 mm dan panjang 30 mm. Batang kemudian dipotong lagi menjadi spesimen berbentuk cakram. Untuk memastikan apakah sampel adalah BMG atau tidak, sampel dievaluasi dengan Scanning Electron Microscopy (SEM), Energy Dispersion Spectrometer (EDS), Differential Scanning Calorimetry (DSC), Electron Probe X-ray Micro Analyzer (EPMA), dan X -ray Difraction (XRD). Hasilnya dibahas dalam penelitian ini. Kata Kunci: Bulk Metallic Glasses, Cu45Zr45Al5Ag5, Pengecoran Cetakan di Tembaga.

scholarly journals Correlation between fracture surface morphology and toughness in Zr-based bulk metallic glasses

2010 ◽  
Vol 25 (5) ◽  
pp. 982-990 ◽  
Author(s):  
Jin-Yoo Suh ◽  
R. Dale Conner ◽  
C. Paul Kim ◽  
Marios D. Demetriou ◽  
William L. Johnson
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Scanning Electron Microscopy ◽  
Energy Dissipation ◽  
Fracture Surface ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Fracture Surface Morphology ◽  
Scanning Electron

Fracture surfaces of Zr-based bulk metallic glasses of various compositions tested in the as-cast and annealed conditions were analyzed using scanning electron microscopy. The tougher samples have shown highly jagged patterns at the beginning stage of crack propagation, and the length and roughness of this jagged pattern correlate well with the measured fracture toughness values. These jagged patterns, the main source of energy dissipation in the sample, are attributed to the formation of shear bands inside the sample. This observation provides strong evidence of significant “plastic zone” screening at the crack tip.

Investigation of Structure and Properties of the Al–Y–Ni–Co–Cu Metallic Glasses

2002 ◽  
Vol 17 (5) ◽  
pp. 1014-1018 ◽  
Author(s):  
Dmitri V. Louzguine ◽  
Akihisa Inoue
Keyword(s):  
Electron Microscopy ◽  
Metallic Glasses ◽  
Crystallization Behavior ◽  
Supercooled Liquid ◽  
Partial Replacement ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron

The present paper reports the effect of partial replacement of Ni by Cu in the Al85Y8Ni5Co2 alloy. The studied alloys were produced by rapid solidification. Glass-formation, crystallization behavior, and stability of the supercooled liquid were studied by x-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. Partial replacement of Ni by Cu in the Al85Y8Ni5Co2 metallic glass caused formation of the nanoscale α–Al particles and resulted in a decrease in the crystallization temperature and disappearance of the supercooled liquid.

Plasticity of bulk metallic glasses improved by controlling the solidification condition

2008 ◽  
Vol 23 (4) ◽  
pp. 941-948 ◽  
Author(s):  
Z.W. Zhu ◽  
S.J. Zheng ◽  
H.F. Zhang ◽  
B.Z. Ding ◽  
Z.Q. Hu ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Solidification Condition ◽  
X Ray ◽  
Transmission Electron ◽  
Injection Casting

Different bulk metallic glasses (BMGs) were prepared in ductile Cu47.5Zr47.5Al5, Zr62Cu15.4Ni12.6Al10, and brittle Zr55Ni5Al10Cu30 alloys by controlling solidification conditions. The achieved microstructures were characterized by x-ray diffraction, differential scanning calorimetry, transmission electron microscopy, and synchrotron- based high-energy x-ray diffraction. Monolithic BMGs obtained by high-temperature injection casting are brittle, while BMGs bearing some nanocrystals with the size of 3 to 7 nm and 2 to 4 nm, obtained by low-temperature injection casting and in situ suction casting, respectively, exhibit good plasticity. It indicates that the microstructures of BMGs are closely affected by the solidification conditions. Controlling the solidification conditions could improve the plasticity of BMGs.

scholarly journals Copper Based Bulk Metallic Glasses for Medical Devices

2019 ◽  
Vol 56 (4) ◽  
pp. 700-704
Author(s):  
Carmen Opris ◽  
Cosmin Codrean ◽  
Dragos Buzdugan ◽  
Petru Hididis
Keyword(s):  
Medical Devices ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Copper Mold Casting ◽  
Mold Casting ◽  
Materials Used

Bulk metallic glasses (BMGs) represent a viable alternative for replacing classic materials used in medical devices. This paper presents the research conducted in order to obtain copper based BMGs using two different chemical compositions: Cu48Zr47Al5 and Cu45Zr45Al5Ag5. The samples were obtained by copper mold casting and their structure and properties were investigated using X-Ray diffraction (XRD), differential scanning calorimetry (DSC) and optical microscopy.

Defect Analyses of Deformed Zr-Cu-Ni-Al Bulk Metallic Glasses

2009 ◽  
Vol 283-286 ◽  
pp. 453-457
Author(s):  
Jung Hoon Yoo ◽  
Dae Hwang Yoo ◽  
Jung Hwa Seo ◽  
Ji Ling Dong ◽  
Young Sang Na ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Plastic Deformation ◽  
Metallic Glasses ◽  
Shear Bands ◽  
Bulk Metallic Glasses ◽  
Electron Holography ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Localized Plastic Deformation

In Zr-Cu-Ni-Al bulk metallic glasses where there are no dislocations, localized plastic deformation in shear bands occurs largely by the formation and migration of defects such as voids, micropores, shear bands and local variations in composition. Thus, the investigation on defects is critical for the understanding and improvement of plastic deformation in metallic glasses. In this study, microstructures and nano defects in the Zr-Cu-Ni-Al BMGs are characterized by variety of techniques, such as X-ray diffractometry, high resolution transmission electron microscopy, scanning transmission electron microscopy and electron holography.

Elastic Properties of Three Bulk Metallic Glasses. Evolution Versus Temperature in the Glass Transition Region and Influence of Crystallisation.

2000 ◽  
Vol 644 ◽  
Author(s):  
B. Van De Moortele ◽  
J.M. Pelletier ◽  
J.L. Soubeyroux ◽  
I.R. Lu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Glass Transition ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
X Ray Diffraction ◽  
Mechanical Spectroscopy ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron

AbstractThree bulk metallic glasses, with different resistance against crystallisation, were investigated using DSC experiments, X-ray diffraction, transmission electron microscopy and mechanical spectroscopy. Like in other non-crystalline materials, the elastic modulus exhibits a large decrease above the glass transition temperature. In materials with a large supercooled region (Pd-Ni-Cu-P for instance), this decrease can reach three decades, leading to an attractive glass forming ability. In contrast, in bulk metallic glasses in which onset of crystallisation occurs very rapidly above Tg, this decrease is on less than one decade. A correlation is made with the microstructure evolution revealed by X-Ray diffraction and transmission electron microscopy.

Electron microscopy of crystalline structure in thermotropic random copolymers

1991 ◽  
Vol 49 ◽  
pp. 1054-1055
Author(s):  
Afzana Anwer ◽  
S. Eilidh Bedford ◽  
Richard J. Spontak ◽  
Alan H. Windle
Keyword(s):  
Electron Microscopy ◽  
Crystalline Structure ◽  
Liquid Crystalline ◽  
Elevated Temperatures ◽  
Random Copolymers ◽  
Molecular Characteristics ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Identical Monomer ◽  
Periodic Layer

Random copolyesters composed of wholly aromatic monomers such as p-oxybenzoate (B) and 2,6-oxynaphthoate (N) are known to exhibit liquid crystalline characteristics at elevated temperatures and over a broad composition range. Previous studies employing techniques such as X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) have conclusively proven that these thermotropic copolymers can possess a significant crystalline fraction, depending on molecular characteristics and processing history, despite the fact that the copolymer chains possess random intramolecular sequencing. Consequently, the nature of the crystalline structure that develops when these materials are processed in their mesophases and subsequently annealed has recently received considerable attention. A model that has been consistent with all experimental observations involves the Non-Periodic Layer (NPL) crystallite, which occurs when identical monomer sequences enter into register between adjacent chains. The objective of this work is to employ electron microscopy to identify and characterize these crystallites.

scholarly journals Tension-Tension Fatigue Behavior of High-Toughness Zr61Ti2Cu25Al12 Bulk Metallic Glass

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2815
Author(s):  
Yu Hang Yang ◽  
Jun Yi ◽  
Na Yang ◽  
Wen Liang ◽  
Hao Ran Huang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Shear Band ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Fatigue Resistance ◽  
Metallic Glasses ◽  
Stress Amplitude ◽  
Fatigue Behavior ◽  
Bulk Metallic Glasses ◽  
High Toughness

Bulk metallic glasses have application potential in engineering structures due to their exceptional strength and fracture toughness. Their fatigue resistance is very important for the application as well. We report the tension-tension fatigue damage behavior of a Zr61Ti2Cu25Al12 bulk metallic glass, which has the highest fracture toughness among BMGs. The Zr61Ti2Cu25Al12 glass exhibits a tension-tension fatigue endurance limit of 195 MPa, which is higher than that of high-toughness steels. The fracture morphology of the specimens depends on the applied stress amplitude. We found flocks of shear bands, which were perpendicular to the loading direction, on the surface of the fatigue test specimens with stress amplitude higher than the fatigue limit of the glass. The fatigue cracking of the glass initiated from a shear band in a shear band flock. Our work demonstrated that the Zr61Ti2Cu25Al12 glass is a competitive structural material and shed light on improving the fatigue resistance of bulk metallic glasses.

scholarly journals Inverse Design of Fe-Based Bulk Metallic Glasses Using Machine Learning

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 729
Author(s):  
Junhyub Jeon ◽  
Namhyuk Seo ◽  
Hwi-Jun Kim ◽  
Min-Ha Lee ◽  
Hyun-Kyu Lim ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Metallic Glasses ◽  
Alloy Composition ◽  
Relevant Literature ◽  
Bulk Metallic Glasses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ann Models ◽  
Wide Scale ◽  
Artificial Neural Network Ann

Fe-based bulk metallic glasses (BMGs) are a unique class of materials that are attracting attention in a wide variety of applications owing to their physical properties. Several studies have investigated and designed the relationships between alloy composition and thermal properties of BMGs using an artificial neural network (ANN). The limitation of the wide-scale use of these models is that the required composition is yet to be found despite numerous case studies. To address this issue, we trained an ANN to design Fe-based BMGs that predict the thermal properties. Models were trained using only the composition of the alloy as input and were created from a database of more than 150 experimental data of Fe-based BMGs from relevant literature. We adopted these ANN models to design BMGs with thermal properties to satisfy the intended purpose using particle swarm optimization. A melt spinner was employed to fabricate the designed alloys. X-ray diffraction and differential thermal analysis tests were used to evaluate the specimens.

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