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The Hellenistic, Roman, and Medieval Glass from Cosa
The Hellenistic, Roman, and Medieval Glass from Cosa continues the exemplary record of publication by the American Academy in Rome on important classes of materials recovered in excavation from one of the principal archaeological sites of Roman Italy. Over 15,000 fragments of glass tableware, ranging in date from the mid-second century BCE to the early fifth century CE, were found at Cosa, a small town in Etruria (modern Tuscany). Cosa's products were chiefly exported to North Africa and Europe, but its influence was felt throughout the Mediterranean world. The research and analysis presented here are the work of the late David Frederick Grose, who began this project when no other city site excavations in Italy focused on ancient glass. He confirmed that the Roman glass industry began to emerge in the Julio-Claudian era, beginning in the principate of Augustus. His study traces the evolution of manufacturing techniques from core-formed vessels to free blown glass, and it documents changes in taste and style that were characteristic of the western glass industry throughout its long history. At the time of Grose's unexpected passing, his study was complete but not yet published. Nevertheless, the reputation of his work in this area has done much to establish the value and importance of excavating and researching Cosa's glass. This volume, arranged and edited by R.T. Scott, makes Grose's essential scholarship on the subject available for the first time.
Book
Strain-hardening and suppression of shear-banding in rejuvenated bulk metallic glass
Strain-hardening (the increase of flow stress with plastic strain) is the most important phenomenon in the mechanical behaviour of engineering alloys because it ensures that flow is delocalized, enhances tensile ductility and inhibits catastrophic mechanical failure
1
,
2
. Metallic glasses (MGs) lack the crystallinity of conventional engineering alloys, and some of their properties—such as higher yield stress and elastic strain limit
3
—are greatly improved relative to their crystalline counterparts. MGs can have high fracture toughness and have the highest known ‘damage tolerance’ (defined as the product of yield stress and fracture toughness)
4
among all structural materials. However, the use of MGs in structural applications is largely limited by the fact that they show strain-softening instead of strain-hardening; this leads to extreme localization of plastic flow in shear bands, and is associated with early catastrophic failure in tension. Although rejuvenation of an MG (raising its energy to values that are typical of glass formation at a higher cooling rate) lowers its yield stress, which might enable strain-hardening
5
, it is unclear whether sufficient rejuvenation can be achieved in bulk samples while retaining their glassy structure. Here we show that plastic deformation under triaxial compression at room temperature can rejuvenate bulk MG samples sufficiently to enable strain-hardening through a mechanism that has not been previously observed in the metallic state. This transformed behaviour suppresses shear-banding in bulk samples in normal uniaxial (tensile or compressive) tests, prevents catastrophic failure and leads to higher ultimate flow stress. The rejuvenated MGs are stable at room temperature and show exceptionally efficient strain-hardening, greatly increasing their potential use in structural applications.
Bulk metallic glasses can acquire the ability to strain-harden through a mechanical rejuvenation treatment at room temperature that retains their non-crystalline structure.
Journal Article
High-temperature bulk metallic glasses developed by combinatorial methods
Since their discovery in 1960
1
, metallic glasses based on a wide range of elements have been developed
2
. However, the theoretical prediction of glass-forming compositions is challenging and the discovery of alloys with specific properties has so far largely been the result of trial and error
3
–
8
. Bulk metallic glasses can exhibit strength and elasticity surpassing those of conventional structural alloys
9
–
11
, but the mechanical properties of these glasses are critically dependent on the glass transition temperature. At temperatures approaching the glass transition, bulk metallic glasses undergo plastic flow, resulting in a substantial decrease in quasi-static strength. Bulk metallic glasses with glass transition temperatures greater than 1,000 kelvin have been developed, but the supercooled liquid region (between the glass transition and the crystallization temperature) is narrow, resulting in very little thermoplastic formability, which limits their practical applicability. Here we report the design of iridium/nickel/tantalum metallic glasses (and others also containing boron) with a glass transition temperature of up to 1,162 kelvin and a supercooled liquid region of 136 kelvin that is wider than that of most existing metallic glasses
12
. Our Ir–Ni–Ta–(B) glasses exhibit high strength at high temperatures compared to existing alloys: 3.7 gigapascals at 1,000 kelvin
9
,
13
. Their glass-forming ability is characterized by a critical casting thickness of three millimetres, suggesting that small-scale components for applications at high temperatures or in harsh environments can readily be obtained by thermoplastic forming
14
. To identify alloys of interest, we used a simplified combinatorial approach
6
–
8
harnessing a previously reported correlation between glass-forming ability and electrical resistivity
15
–
17
. This method is non-destructive, allowing subsequent testing of a range of physical properties on the same library of samples. The practicality of our design and discovery approach, exemplified by the identification of high-strength, high-temperature bulk metallic glasses, bodes well for enabling the discovery of other glassy alloys with exciting properties.
Bulk metallic glasses made from alloys of iridium, nickel, tantalum and boron are developed by combinatorial methods, with higher strength at high temperature than those previously produced.
Journal Article
Three-dimensional printing of multicomponent glasses using phase-separating resins
The digital fabrication of oxide glasses by three-dimensional (3D) printing represents a major paradigm shift in the way glasses are designed and manufactured, opening opportunities to explore functionalities inaccessible by current technologies. The few enticing examples of 3D printed glasses are limited in their chemical compositions and suffer from the low resolution achievable with particle-based or molten glass technologies. Here, we report a digital light-processing 3D printing platform that exploits the photopolymerization-induced phase separation of hybrid resins to create glass parts with complex shapes, high spatial resolutions and multi-oxide chemical compositions. Analogously to conventional porous glass fabrication methods, we exploit phase separation phenomena to fabricate complex glass parts displaying light-controlled multiscale porosity and dense multicomponent transparent glasses with arbitrary geometry using a desktop printer. Because most functional properties of glasses emerge from their transparency and multicomponent nature, this 3D printing platform may be useful for distinct technologies, sciences and arts.
Photopolymerization-induced phase separation of resins enables the high-resolution 3D printing of glass oxides with intricate shapes and distinct chemical composition.
Journal Article
Self-assembly of nanostructured glass metasurfaces via templated fluid instabilities
Modern devices require the tuning of the size, shape and spatial arrangement of nano-objects and their assemblies with nanometre-scale precision, over large-area and sometimes soft substrates. Such stringent requirements are beyond the reach of conventional lithographic techniques or self-assembly approaches. Here, we show nanoscale control over the fluid instabilities of optical thin glass films for the fabrication of self-assembled all-dielectric optical metasurfaces. We show and model the tailoring of the position, shape and size of nano-objects with feature sizes below 100 nm and with interparticle distances down to 10 nm. This approach can generate optical nanostructures over rigid and soft substrates that are more than tens of centimetres in size, with optical performance and resolution on a par with advanced traditional lithography-based processes. To underline the potential of our approach, which reconciles high-performance optical metasurfaces and simple self-assembly fabrication approaches, we demonstrate experimentally and via numerical simulation sharp Fano resonances with a quality factor, Q, as high as ∼300 in the visible for all-dielectric nanostructures, to realize protein monolayer detection.Optical glasses can form high-quality dielectric metasurfaces by controlled dewetting and fluid instabilities.
Journal Article
Geometric Frustration of Icosahedron in Metallic Glasses
Icosahedral order has been suggested as the prevalent atomic motif of supercooled liquids and metallic glasses for more than half a century, because the icosahedron is highly close-packed but is difficult to grow, owing to structure frustration and the lack of translational periodicity. By means of angstrom-beam electron diffraction of single icosahedra, we report experimental observation of local icosahedral order in metallic glasses. All the detected icosahedra were found to be distorted with partially face-centered cubic symmetry, presenting compelling evidence on geometric frustration of local icosahedral order in metallic glasses.
Journal Article
FTIR, UV–Vis–NIR spectroscopy, and gamma rays shielding competence of novel ZnO-doped vanadium borophosphate glasses
Structural, optical, and gamma radiation safety properties of 46V
2
O
5
·46P
2
O
5
·(8–
x
)B
2
O
3
·
x
ZnO (
x
= 0,2,4,6, and 8 mol%) abbreviated as VPB/Zn glasses were investigated. The structure of the synthesized glasses has been examined via FTIR spectra within the range of 400–1500 cm
−1
at room temperature. UV–Vis–NIR measurements of the proposed glasses were performed within the range of 200–3300 nm. The optical characteristics such as optical energy bandgap (
E
Optical
), refractive index (
n
Linear
), and Urbach’s energy (
E
U
) have been determined. In addition, the mass attenuation coefficients (MAC) for VPB/Zn glasses were performed utilizing MCNP-5 simulation code and XCOM program for various gamma ray energy varied in range 0.015–15 MeV. Based on MAC values, the equivalent atomic number (
Z
eq
) and buildup factors (EABF and EBF) were evaluated. Results reveal that the direct
E
Optical
Tauc
′
s
of the VPB/Zn glasses ranged from 0.688 to 0.710 eV, while from 0.560 to 0.647 eV for the indirect transition. The admission of the ZnO improves the MAC of the VPB/Zn glasses. Thus, one can conclude that the proposed glasses can be applied for optical devices as semiconductor glasses and considered as good materials for γ-rays shielding.
Journal Article
Synthesis of novel AgO-doped vanadium–borophosphate semiconducting glasses and investigation of their optical, structural, and thermal properties
Ag-doped vanadium–borophosphate glasses having 46V
2
O
5
–46P
2
O
5
–(8 −
x
)B
2
O
3
–
x
AgO as the base structure have been successfully synthesized with different compositions of AgO (
x
= 0, 2, 4, 6, 8 mol%) by the conventional melt-quenching technique. Density and molar volume values were calculated by Archimedes principle. The transmittance and absorbance spectra, XRD, and FTIR measurements of the glasses were performed at room temperature. While XRD data showed that the glasses had an amorphous structure away from crystallization, FTIR spectra showed that vanadium and phosphate compounds forming the glass network consisted of VO
4
, VO
5
and PO
3
, PO
2
structural units, respectively. It was observed that AgO, which replaces B
2
O
3
, acted as a modifier in the glass network. Direct and indirect band gaps of synthesized glasses were calculated using Tauc method. Urbach energies were also calculated. The glass transition temperature, crystallization temperature, and melting temperature values of the samples were determined with differential scanning calorimetry (DSC) in the range of room temperature to 1000 °C.
Journal Article
Combinatorial development of bulk metallic glasses
The identification of multicomponent alloys out of a vast compositional space is a daunting task, especially for bulk metallic glasses composed of three or more elements. Despite an increasing theoretical understanding of glass formation, bulk metallic glasses are predominantly developed through a sequential and time-consuming trial-and-error approach. Even for binary systems, accurate quantum mechanical approaches are still many orders of magnitude away from being able to simulate the relatively slow kinetics of glass formation. Here, we present a high-throughput strategy where ∼3,000 alloy compositions are fabricated simultaneously and characterized for thermoplastic formability through parallel blow forming. Using this approach, we identified the composition with the highest thermoplastic formability in the glass-forming system Mg–Cu–Y. The method provides a versatile toolbox for unveiling complex correlations of material properties and glass formation, and should facilitate a drastic increase in the discovery rate of metallic glasses.
For metallic glasses composed of three or more elements, optimizing their composition to satisfy a combination of properties is a formidable task. Now, a high-throughput strategy that can simultaneously fabricate thousands of alloy compositions and characterize them for thermoplastic formability through parallel blow forming makes possible the identification of the alloy composition with the highest thermoplastic formability.
Journal Article
Ultrastable glasses from in silico vapour deposition
Glasses are generally prepared by cooling from the liquid phase, and their properties depend on their thermal history. Recent experiments indicate that glasses prepared by vapour deposition onto a substrate can exhibit remarkable stability, and might correspond to equilibrium states that could hitherto be reached only by glasses aged for thousands of years. Here we create ultrastable glasses by means of a computer-simulation process that mimics physical vapour deposition. These stable glasses have, far below the conventional glass-transition temperature, the properties expected for the equilibrium supercooled liquid state, and optimal stability is attained when deposition occurs at the Kauzmann temperature. We also show that the glasses’ extraordinary stability is associated with distinct structural motifs, in particular the abundance of regular Voronoi polyhedra and the relative lack of irregular polyhedra.
Glasses with extraordinary kinetic stability have been made in the laboratory by physical vapour deposition. A computational algorithm that mimics such a deposition process now reveals that deposition at the temperature at which the configurational entropy vanishes leads to ultrastable glasses that are truly amorphous, pack uniformly and have energies that are equivalent to those of equilibrium supercooled liquids.
Journal Article