Seminar Talk

17274 1547029112

Phase Transitions in Non-Equilibrium Metallic Systems

  • Date: Jan 18, 2019
  • Time: 11:00 - 12:00
  • Speaker: Prof. Stefan Pogatscher
  • Distinguished Professor for Materials Engineering of Aluminum, Chair of Nonferrous Metallurgy, Montanuniversitaet Leoben, Austria
  • Location: Max-Planck-Institut für Eisenforschung GmbH
  • Room: Seminar Room 1
  • Host: Prof. Dierk Raabe
  • Contact: rco@mpie.de
Nearly all classes of materials show non-equilibrium phase transitions and the first technological use of quenching metals for designing properties is documented as ~800 BC. However, the decomposition towards equilibrium is still difficult to understand due to the strong non-equilibrium kinetics. Two examples are discussed: First the decomposition of a quenched super saturated solid solution and second the decomposition of a quenched metallic melt. In the first example the technological important AlMgSi alloys are addressed. Low temperature solute clustering, its implications on aging and the effect of trace elements are discussed. Moreover, it is shown which physical pre-requisites need to be fulfilled to modify diffusion by orders of magnitude and to examine a “diffusion on demand” concept. In the second example the first solid–solid transition via melting in a metal, detected upon the decomposition of a metallic glass, is demonstrated. The transformation path is discussed under its thermodynamic and kinetic prerequisites. Moreover, the capabilities of the applied novel technique of fast scanning calorimetry is addressed. Finally, it is outlined how this technique links the two examples via its potential for in-situ measuring the non-equilibrium vacancy evolution.
 
loading content
Go to Editor View