Ofertes per a estudiants

Oferta de Beca

Study of metallic glass dynamics

Ph.D. grant funded by MINECO, grant FIS2017-82625-P, Vidrios organicos y metalicos: dinamica, recristalizacion y propiedades vibracionales.

Of the different states of matter, the liquid and the glass states are the more complex ones. They consist of strongly interacting atoms or molecules but they lack the long range translational order of the crystalline solid state. In addition to the intrinsic disordered structure, when approaching glass transition the structural dynamics of liquids slow down orders of magnitude until reaching the glass state, where the typical time for molecular rearrangements is from hundreds of minutes to years depending on the particular glass configuration. The study of these slow dynamics is important in different ways. Firstly, it determines how glasses respond to external stimulus and, therefore, their behavior in technological applications. Secondly, it determines their physical aging behavior, this is how the material changes from one glass configuration to another. This latter point is central for understanding the physics of the glass state. The long times characteristic of the dynamics of supercooled liquids and glasses are a big challenge in order to study these systems both by experiments and simulation.

Metallic glasses are amorphous materials obtained by rapid quenching of metallic melts. Due to the lack of long-range order, metallic glasses show some outstanding properties which makes them good candidates for multiple applications. Furthermore, due to the quasi-isotropy of the metallic bond metallic glasses are rather “simple” glasses whose properties are essentially due to their topological disorder. This fact makes metallic glasses very interesting materials to understand the universal properties of the glass state and glass-transition related phenomena. The research group in which the PhD project will be developed has been working in metallic glass-forming systems since several years [1-2].

Molecular Dynamics (MD) is a well-established technique in the simulation of materials’ properties and it has been used in the study of glasses and metallic glasses. However, it is well established that the properties of glasses are dependent on the glass configuration achieved during the glass transition from the liquid. This poses an enormous difficulty for obtaining realistic glass configurations by simulation. For instance, in the case of metallic glasses the experimental quenching rates, between 10 and 106 K s-1, are far-off orders of magnitude from the quenching rates, from 1013 to 109 K s-1, feasible by Molecular Dynamics simulations. Thus, direct comparison of MD simulation results with experimental data is always taken with precaution. The Swap Monte-Carlo Molecular Dynamics is an emerging technique [3-4] which allows to simulate the glassy state obtained within the range of experimental quenching rates.

The present Ph.D. project aims to study the structure and dynamics of metallic glasses by using the Swap Monte-Carlo MD method in combination with experimental techniques on real materials. The study will be focused on solving some of the questions currently being debated in the glass science community, namely: What are the interrelations and dependencies among dynamics at different time and length scales? How the microscopic dynamics give rise to the macroscopic response and what is the relative contribution of each length scale? Advances in answering these questions are necessary to better understand the metallic glass state and to control the properties of these advanced technological materials.

Interested, please contact:
Daniel Crespo
Group of Characterization of Materials, UPC
Escola d’Enginyeria de Barcelona-Est
Daniel.Crespo@upc.edu, before July 15th, 2018

  1. D. Crespo et al., Phonon dispersion relation of metallic glasses, Phys. Rev B 94 (2016) 144205
  2. M. Lüttich et al., Anti-aging in ultrastable metallic glasses, Phys. Rev. Lett. 120, (2018) 135504
  3. A. Ninarello et al., Models and Algorithms for the Next Generation of Glass Transition Studies, Phys. Rev. X 7 (2017) 021039
  4. H. Ikeda et al., Mean field theory of the swap Monte Carlo algorithm, J. Chem. Phys. 147 (2017) 234506

Oferta de tesi doctoral:
Study and improvement of the mechanical properties of metallic glasses

Metallic glasses are amorphous alloys with liquid-like atomic structure. These materials allow the study of fundamental physical and materials science subjects such as glass transition and atomic mobility in disordered matter. Furthermore, metallic glasses are expected to be excellent materials for advanced technological applications due to their unconventional properties.

The PhD thesis will be realized in the PhD program Applied Physics and Scientific Simulation of the Universitat Politècnica de Catalunya. Research activity will be developed within the Group of Characterization of Materials, it will comprise theoretical and experimental work and participation in neutron and synchrotron experiments. This project is adequate for students with Physics, Chemistry and Materials Science degrees.

Oferta de treballs finals de carrera

El grup de materials metaestables i nanoestructurats ofereix la possibilitat als estudiants d'enginyeria de la UPC de realitzar treballs finals de carrera. Els projectes s'emmarquen dins la recerca en ciència de materials actual del grup, permetent als estudiants conèixer i interactuar amb els mètodes i les tècniques experimentals utilitzades en la recerca científica. Els resultats de varis dels treballs finals de carrera realitzats han estat presentats en congressos i comunicacions científiques internacionals. Contacteu amb nosaltres per demanar-nos informació.

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