Bulk Metallic Glasses: At the Cutting Edge of Metals Research

Abstract

Glassy alloys (metallic glasses) are currently the focus of intense research in the international metals community. Setting aside elevated-temperature applications, these amorphous metals have exciting potential for structural applications. When metallic glasses were first widely studied in the 1960s, the alloy compositions then known to be quenchable into the glassy state from the liquid required high cooling rates on the order of 10 6 K s −1 and were consequently restricted to thin sections. The current interest in metallic glasses has its origin mainly in the increasing range of compositions that can now be cast into glasses at much lower cooling rates, permitting minimum sections of 1 mm to 1 cm or even larger. These bulk metallic glasses (BMGs) are the focus of the articles in this issue of MRS Bulletin. Our goal is to illustrate the major materials issues for BMGs, from processing to structures to properties and from the fundamental science of glasses to viable industrial applications. We hope that the articles, in providing a snapshot of a rapidly moving field, show why BMGs are attracting such intense interest and serve to highlight some challenging issues awaiting resolution.

Shear transformation zone volume determining ductile–brittle transition of bulk metallic glasses

“…Bulk metallic glasses (BMGs) represent a relatively young class of materials envisaged for many functional and structural applications [1][2][3][4][5]. Crystalline alloys usually have the ductile-to-brittle transition (DBT) temperature that is determined by the dislocation movements.…”

Thermodynamic Stability of Transition States in Nanosystems

“…As known [28][29][30][31], amorphization of multi-component materials has strictly kinetic origin-that is, at least one internal relaxation time crosses an experimental time scale. Such materials do not possess any kind of thermodynamic stability and may be understood as liquids that have lost their ability to flow.…”

“…A typical amorphization path involves a high-temperature stage of preparation and a low-temperature stage of analysis or usage [28][29][30][31][32][33][34][35][36][37][38]. Our stability analysis is relevant to the high-temperature stage of preparation of the amorphous phases of pure substances.…”

Viscous surface flow induced on Ti-based bulk metallic glass by heavy ion irradiation

“…Because of their unique mechanical and chemical properties, such as high strength and superior resistance to corrosion, metallic glasses (MGs) have attracted great interest in recent decades [1][2][3][4][5]. Due to their inherent disordered structure, they are supposed to be ideal potential candidates for application in nuclear-irradiated environments or deep space.…”