• Speaker: Dr. Kostas Geogarakis
  • Institution: School of Aerospace Transport and Manufacturing Cranfield University, UK
  • Date: 24.11. 2017
  • Place: CEITEC Brno University of Technology

Anotation: 

The high flux pulsed reactor IBR-2 in Frank Laboratory of Neutron Physics at Joint
Bulk Metallic Glasses (BMGs) are metastable materials that lack the long range order of
conventional crystalline metals. Easy bulk glass forming alloys are usually multicomponent
eutectic or near eutectic liquid compositions with high viscosities and depressed melting
temperatures that result in reduced critical cooling rates required for suppression of crystal
nucleation and growth. Their disordered atomic structure results in various remarkable
engineering properties, such as high mechanical strength up to 5 GPa, elasticity up to 2%
strain, good corrosion and wear resistance and excellent soft magnetic properties. The
combination of their unique properties with their good formability through viscous flow in
the supercooled liquid state makes them highly attractive for a wide range of high-end
applications.
The amorphous atomic structure of BMGs is formed when a melted alloy is cooled rapidly
enough so that crystallization is avoided upon solidification. However, the way the atomic
structure of the liquid transforms to the glassy structure is generally unknown, mainly
because the acquisition of structural information in the supercooled liquid regime is
hindered by crystallization. Recent advances in containerless solidification methods offer
new possibilities to study the undercooled metallic liquids using synchrotron and neutron
radiation and to probe the structural evolution during vitrification. In this lecture, we will
discuss the latest advances in understating glass formation by in-situ probing the structural
pathway of liquid metals to vitrifaction using modern characterization techniques. We will
also focus on the structure and property relation of metallic glasses and discuss about the
challenges and future potential of this exceptional class of materials.

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Photogallery