Dresden 2014 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 4: Computational Materials Modelling I - High throughput/Material discovery

MM 4.2: Vortrag

Montag, 31. März 2014, 10:30–10:45, IFW D

High-throughput studies multi-component Ni-rich alloys — •Michaela Höfler, Sascha B. Maisel, and Stefan Müller — Institute of Advanced Ceramics, TUHH, 21073 Hamburg, Deutschland

We present high-throughput studies of various Ni-rich alloys (Ni-Al, Ni-Ta, Ni-W, Ni-Ta-W, Al-Ni-W, Al-Ni-Ta, Al-Ni-Ta-W and Al-Ni-Ta-W) based on DFT theory guided by the cluster-expansion method. We present CE Hamiltonians, which accurately describe the ground-state behavior of the binary alloys and and discuss ternary ground-state compounds Al₇Ni₂₄W₁, Al₃Ni₁₂W₁ and Al₃Ni₁₂Ta₁ found to be stable in multi-component alloys across a data base of over 600 fully-relaxed DFT superstructures with up to four components. The resulting ground-states structures have substitutional L1₂-type order and release nearly 0.5 meV/atom of enthalpy upon formation. Our findings indicate that ternary γ′-derivates of Al_xN₃Ta_1−x and Al_xN₃W_1−x stoichiometries are energetically favourable over true quarternary Al-Ni-Ta-W compounds at low temperatures.