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MM: Fachverband Metall- und Materialphysik
MM 2: Topical session: Integrated computational materials engineering for design of new materials I
MM 2.2: Vortrag
Montag, 7. März 2016, 10:45–11:00, H38
Facet-controlled phase separation in supersaturated Au-Ni nanoparticles upon shape equilibration — Andreas Herz1, •Martin Friák2,3, Diana Rossberg1, Martina Hentschel1, Felix Theska1, Dong Wang1, David Holec4, Mojmǐr Šob3,2,5, Oldřich Schneeweiss2, and Peter Schaaf1 — 1TU Ilmenau, Ilmenau, Germany — 2Institute of Physics of Materials, AS CR, Brno, Czech Republic — 3CEITEC MU, Masaryk University, Brno, Czech Republic — 4Montanuniversität Leoben, Leoben, Austria — 5Dept. of Chem., Faculty of Science, Masaryk University, Brno, Czech Republic
Solid-state dewetting is used to fabricate supersaturated, submicron-sized Au-Ni solid solution particles out of thin Au/Ni bilayers by means of a rapid thermal annealing technique. Phase separation in such particles is studied with respect to their equilibrium crystal (or Wulff) shape by subsequent annealing at elevated temperature. It is found that {100} faceting planes of the equilibrated particles are enriched with Ni and {111} faces with Au. Both phases are treated by quantum-mechanical calculations in combination with an error-reduction scheme that was developed to compensate for a missing exchange-correlation potential that would reliably describe both Au and Ni. The observed phase configuration is then related to the minimization of strongly anisotropic elastic energies of Au- and Ni-rich phases and results in a rather unique nanoparticle composite state that is characterized by nearly uniform value of elastic response to epitaxial strains all over the faceted surface. This work demonstrates a route for studying features of physical metallurgy at the mesoscale (APL 107 (2015) 073109).