Amorphous alloys were first developed over 40 years ago and found applications as magnetic core or reinforcement added to other materials. The scope of applications is limited due to the small thickness in the region of only tens of microns. The research effort in the past two decades, mainly pioneered by a Japanese- and a US-group of scientists, has substantially relaxed this size constrain. Some bulk metallic glasses can have tensile strength up to 3000 MPa with good corrosion resistance, reasonable toughness, low internal friction and good processability. Bulk metallic glasses are now being used in consumer electronic industries, sporting goods industries, etc. In this paper, the authors reviewed the recent development of new alloy systems of bulk metallic glasses. The properties and processing technologies relevant to the industrial applications of these alloys are also discussed here. The behaviors of bulk metallic glasses under extreme conditions such as high pressure and low temperature are especially addressed in this review. In order that the scope of applications can be broadened, the understanding of the glass-forming criteria is important for the design of new alloy systems and also the processing techniques.

https://www.tcd.ie/Physics/people/Graham.Cross/SF%20Poster%202011/Shek-MaterSciEng04-Bulk%20Metallic%20Glasses.pdf

Bulk metallic glasses

https://www.tcd.ie/Physics/people/Graham.Cross/SF%20Poster%202011/Schuh-ActaMater07-Mechanical%20behaviour%20of%20amorphous%20alloys.pdf

Mechanical behavior of amorphous alloys

A microscopic mechanism for steady state inhomogeneous flow in metallic glasses

Atomic-level structure and structure–property relationship in metallic glasses

Shear-banding is a ubiquitous plastic-deformation mode in materials. In metallic glasses, shear bands are particularly important as they play the decisive role in controlling plasticity and failure at room temperature. While there have been several reviews on the general mechanical properties of metallic glasses, a pressing need remains for an overview focused exclusively on shear bands, which have received tremendous attention in the past several years. This article attempts to provide a comprehensive and up-to-date review on the rapid progress achieved very recently on this subject. We describe the shear bands from the inside out, and treat key materials-science issues of general interest, including the initiation of shear localization starting from shear transformations, the temperature and velocity reached in the propagating or sliding band, the structural evolution inside the shear-band material, and the parameters that strongly influence shear-banding. Several new discoveries and concepts, such as stick-slip cold shear-banding and strength/plasticity enhancement at sub-micrometer sample sizes, will also be highlighted. The understanding built-up from these accounts will be used to explain the successful control of shear bands achieved so far in the laboratory. The review also identifies a number of key remaining questions to be answered, and presents an outlook for the field.

Shear bands in metallic glasses

The lower bound in loss for fusion splices is ∼ 0.01 dB due principally to lateral offset of the cores and alteration of the index profile. This paper investigates the effects on loss of viscous flow and diffusion of the glass constituents during fusion, defining their time-temperature dependencies, and changes in index profile.

Splice loss of single-mode fiber as related to fusion time, temperature, and index profile alteration

Hermetic packaging requirements for high-reliability fiber-optic devices can be met through the use of solder-sealed fibre penetrations. Local metallization of the fiber surface facilitates soldering but also modifies the fiber's strength and fatigue properties. A significant body of research addresses the properties of fibers coated with metal during fiber drawing, but the mechanical properties of fibers locally metallized after drawing have not been discussed. These properties were evaluated by means of dynamic fatigue tensile testing for fibres having a multilayer metallization applied by a vacuum deposition process. The results show that fiber strength reduction resulting from metallization is compensated by an increased resistance to static fatigue. Use of the results in reliability assurance is discussed. >

Mechanical reliability of metallized optical fiber for hermetic terminations

Dispersion-shifted single mode fibers have been fabricated with losses as low as 0.21 dB/km in the zero-dispersion region ( \lambda_{0} \approx 1.5-1.6 \mu m). Low-loss (average = 0.06-dB) fusion splices have been made with the chlorine-hydrogen flame fusion technique. The recoated splices show strengths in excess of 300 kpsi. The fibers have been incorporated into a cable structure with negligible change in loss.

Optical transmission in dispersion-shifted single mode spliced fibers and cables

Three hundred kilometers of single-mode fiber exhibiting median optical losses of 0.19 dB/km at 1.57 μm have been fabricated from preforms made by a high-rate Modified Chemical Vapor Deposition (MCVD) process. A new fiber design [1] was utilized which minimizes Rayleigh scattering loss by reducing the amount of dopants in the core. Milestone systems experiments incorporating this fiber have already demonstrated 420-Mbit transmission through 203 km [2], 2-Gbit transmission through 130 km [3], 1.37 Tbit km/s using 10 wavelength division multiplexed lasers [4], 4-Gbit through 102 km using a novel electronic multiplexer/demultiplexer [5], and 4 Gbit through 117 km using a Ti:LiNbO 3 external modulator [6]. Additionally, very low induced losses from hydrogen and radiation are reported.

The fabrication and performance of long lengths of silica core fiber

We have discovered that the strength of arc fusion splices in optical fiber can be adversely affected by particles (e.g., SiO₂ particles) from the electrodes. Disclosed is a method of arc fusion splicing that can substantially increase the probability that a given fiber splice will meet a given strength requirement. The method comprises initiating the arc in a "cleaning" position selected such that the probability of incidence on the fibers of particles from the electrodes is relatively low, followed by changing the relative position between the electrodes with the arc therebetween and the fibers to the conventional "heating" position and forming the splice.

J. T. Krause

Papers

Splice loss of single-mode fiber as related to fusion time, temperature, and index profile alteration

Mechanical reliability of metallized optical fiber for hermetic terminations

Optical transmission in dispersion-shifted single mode spliced fibers and cables

The fabrication and performance of long lengths of silica core fiber

Method and apparatus for fusion splicing optical fibers