David Seidman
Northwestern University
Phase separation in the condensed state of matter is of general scientific interest as well as being technologically important. It commences with the formation of subnanometer diameter nuclei, which subsequently evolve temporally by growing and coarsening. Hence, it is the kinetics of phase separation that ultimately leads a system toward its equilibrium thermodynamic state. In this talk I will show how atom-probe tomography is utilized to follow, on an atomic scale, the kinetics of phase separation in ternary alloys, Ni-Al-Cr, beginning with the clustering of atoms to form nuclei that evolve into a precipitates that have an ordered crystal structure. In parallel with the experiments lattice kinetic Monte Carlo simulations are performed, whose results help enormously in obtaining a detailed atomistic understanding of the mechanisms by which phase separation occurs and evolves. The atom-probe tomographic results taken in concert with the Monte Carlo simulations yields a physical portrait that provides a deeper physical understanding of phase separation in a concentrated multicomponent alloy than has heretofore been possible.
Friday, May 8, 2008 at 4:00 PM
Room L211, Technological Institute
Refreshments are served at 3:30 PM
