|About this Abstract
||Materials Science & Technology 2011
||Phase Stability, Diffusion, Kinetics and their Applications (PSDK-VI)
||Coherent Precipitation in Ternary Al Alloys: Insights from First-Principles Modeling
||Colin Ophus, Maarten de Jong, Mark Asta, Ulrich Dahmen, Velimir Radmilovic
|On-Site Speaker (Planned)
This talk will discuss recent insights, derived from the combination of first-principles total energy calculations and statistical-thermodynamic modeling, related to coherent precipitation phenomena in ternary Al-based alloy systems. The studies have been motivated by observations obtained from advanced electron-microscopy and atom-probe-tomography studies in Al-Si-Ge and Al-Sc-Li. In the former system, it is observed that the precipitation of stable diamond-cubic precipitates are preceded by coherent precipitation of nano-scale coherent precipitates that have a mixed Si-Ge content. The results are analyzed in the framework of a first-principles statistical-thermodynamics treatment that explicitly accounts for elastically-mediated interactions within the framework of a Kanazaki-force formalism. We further discuss results obtained by combining first-principles-based thermodynamics methods with mean-field models for diffusion-limited precipitate growth in the Al-Sc-Li system. The results explain that the observed, highly monodisperse size distributions for core-shell precipitates in this system arise from capillary effects that can be readily exploited in designing heat treatments.
||Definite: A CD-only volume