Metallic glasses possess unique mechanical and magnetic properties such as extremely high hardness and have novel applications in many areas including national defense. What prevents the widespread use of metallic glasses is the difficulty in achieving the glassy form due to the low glass forming ability (GFA) of most metallic alloys. The search of new BMCs requires an understanding of GFA on the atomic level and over a wide range of timescales. In this study we used nuclear magnetic resonance (NMR), along with other techniques, to study both structures and atomic motions in Zr-based and Pd-based BMO systems over the entire temperature range from the liquid state down to the glassy state. We observed a clear evidence of a dynamic crossover at temperature Tc above the glass transition temperature Tg. This observation shows that below Tc atomic raffling within cages formed by neighboring atoms freezes rapidly. It demonstrates that such dynamic crossover plays a crucial role in glass transition. Comprehensive studies using NMR, x-ray diffraction, and differential scanning calorimetry revealed the details of nucleation and growth processes in such BMGs and 14.

With contributions from 24 global experts in diverse fields, and edited by world-recognized leaders in physical chemistry, chemical physics and biophysics, Structural Glasses and Supercooled Liquids: Theory, Experiment, and Applications presents a modern, complete survey of glassy phenomena in many systems based on firmly established characteristics of the underlying molecular motions as deduced by first principle theoretical calculations, or with direct/single-molecule experimental techniques. A well-rounded view of a variety of disordered systems where cooperative phenomena, which are epitomized by supercooled liquids, take place is provided. These systems include structural glasses and supercooled liquids, polymers, complex liquids, protein conformational dynamics, and strongly interacting electron systems with quenched/self-generated disorder. Detailed calculations and reasoned arguments closely corresponding with experimental data are included, making the book accessible to an educated non-expert reader.

There has been a renaissance in glass science brought about by the development of concepts such as fragility index and the energy landscape with megabasins. Research on bulk metallic glasses has been explosive since their advent when MRS offered its first book on the topic. In 2000, a second book broadened the scope to include supercooled liquid, bulk glassy and nanocrystalline states. This book enhances the scope to include glass transition in diverse materials such as water, silicate and polymeric melts. Bringing these threads together in an interdisciplinary manner was fruitful and offers proof that while there is much common ground, gaps between various approaches to the glassy state remain to be bridged. Subjects include: the supercooled liquid; glass formability; structural relaxation and dynamics; structure determination and modeling; processing and applications of bulk metallic glasses; mechanical properties; mechanical properties - composites; crystallization; electronic and magnetic structure and properties; and nanoparticles and nonmetallic glasses.

Three properties of bulk metallic glasses were investigated: (1) atomic motions; (2) characteristics of bonding and electronic states; (3) fracture. Atomic motion in glassy PdNiCuP was investigated by NMR over a wide temperature range from below the glass transition temperature Tg to above the liquidus temperature Tliq. This study reveals the temperature in the supercooled liquid region, below which motions of different elements begin to diverge. It sheds light on the nature of the crossover temperature Tc proposed by mode coupling theory. Also, hopping was shown to persist below Tg. The electronic states of various metallic glasses were studied by NMR including CuZrAl, Ce-based, and Y-based alloys. Results established some correlation between the glass forming ability and the characteristics of electronic states. This sheds light on the structure and formation of metallic glasses. Finally, we studied the fracture surfaces of various bulk metallic glasses including the brittle Mg-based bulk metallic glass. We established a clear correlation between the fracture toughness and plastic process zone size for various glasses. The results indicate that the fracture in brittle metallic glassy materials might also proceed through the local softening mechanism but at different length scales.

Central to the field of condensed matter physics is a decades old outstanding problem in the study of glasses -- namely explaining the extreme slowing of dynamics in a liquid as it is supercooled towards the so-called glass transition. Efforts to universally describe the stretched relaxation processes and heterogeneous dynamics that characteristically develop in supercooled liquids remain divided in both their approaches and successes. Towards this end, a consensus on the role that atomic and molecular structures play in the liquid is even more tenuous. However, mounting material science research efforts have culminated to reveal that the vast diversity of metallic glass species and their properties are rooted in an equally-broad set of structural archetypes. Herein lies the motivation of this dissertation: the detailed information available regarding the structure-property relationships of metallic glasses provides a new context in which one can study the evolution of a supercooled liquid by utilizing a structural motif that is known to dominate the glass. Cu_64 Zr_36 is a binary alloy whose good glass-forming ability and simple composition makes it a canonical material to both empirical and numerical studies. Here, we perform classical molecular dynamics simulations and conduct a comprehensive analysis of the dynamical regimes of liquid Cu_64 Zr_36, while focusing on the roles played by atomic icosahedral ordering -- a structural motif which ultimately percolates the glass' structure. Large data analysis techniques are leveraged to obtain uniquely detailed structural and dynamical information in this context. In doing so, we develop the first account of the origin of icosahedral order in this alloy, revealing deep connections between this incipient structural ordering, frustration-limited domain theory, and recent important empirical findings that are relevant to the nature of metallic liquids at large. Furthermore, important dynamical landmarks such as the breakdown of the Stokes-Einstein relationship, the decoupling of particle diffusivities, and the development of general "glassy" relaxation features are found to coincide with successive manifestation of icosahedral ordering that arise as the liquid is supercooled. Remarkably, we detect critical-like features in the growth of the icosahedron network, with signatures that suggest that a liquid-liquid phase transition may occur in the deeply supercooled regime to precede glass formation. Such a transition is predicted to occur in many supercooled liquids, although explicit evidence of this phenomenon in realistic systems is scarce. Ultimately this work concludes that icosahedral order characterizes all dynamical regimes of Cu_64 Zr_36, demonstrating the importance and utility of studying supercooled liquids in the context of locally-preferred structure. More broadly, it serves to confirm and inform recent theoretical and empirical findings that are central to understanding the physics underlying the glass transition.

Volume 32 of Reviews in Mineralogy introduces the basic concepts of melt physics and relaxation theory as applied to silicate melts, then to describe the current state of experimental and computer simulation techniques for exploring the detailed atomic structure and dynamic processes which occur at high temperature, and finally to consider the relationships between melt structure, thermodynamic properties and rheology within these liquids. These fundamental relations serve to bridge the extrapolation from often highly simplified melt compositions studied in the laboratory to the multicomponent systems found in nature. This volume focuses on the properties of simple model silicate systems, which are usually volatile-free. The behavior of natural magmas has been summarized in a previous Short Course volume (Nicholls and Russell, editors, 1990: Reviews in Mineralogy, Vol. 24), and the effect of volatiles on magmatic properties in yet another (Carroll and Holloway, editors, 1994: Vol. 30). The Mineralogical Society of America sponsored a short course for which this was the text at Stanford University December 9 and 10, 1995, preceding the Fall Meeting of the American Geophysical Union and MSA in San Fransisco, with about 100 professionals and graduate students in attendance.