SKM 2023 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 40: Mechanical Properties and Allloy Design

MM 40.3: Vortrag

Donnerstag, 30. März 2023, 16:15–16:30, SCH A 251

Towards understanding the yield stress anomaly of Ni₃Al from the energetics of planar defects — •Xiang Xu^1,2, Xi Zhang², Andrei Ruban^3,4, Siegfried Schmauder¹, and Blazej Grabowski² — ¹Institute for Materials Testing, Materials Science and Strength of Materials, University of Stuttgart, Germany — ²Institute for Materials Science, University of Stuttgart, Germany — ³KTH Royal Institute of Technology, Stockholm, Sweden — ⁴Materials Center Leoben Forschung GmbH, Leoben, Austria

The yield stress anomaly of L1₂ intermetallic compounds, especially Ni₃Al, has been investigated for several decades. It is believed that planar defects, e.g., the complex stacking fault and the antiphase boundaries, play an essential role in the dislocation activities during plastic deformation. However, a thorough temperature dependence of the formation energy of these planar defects is still elusive. Facilitated by the state-of-the-art methodology which acquires different thermal mechanisms, especially the magnetic excitations and the full vibrations, the Gibbs energies of the complex stacking fault and the antiphase boundaries of Ni₃Al were calculated within the ab-initio framework up to the melting temperature. The accurate results obtained here are helpful to scrutinize the available experimentally measured data and provide fruitful insights to understand the mechanism behind the yield stress anomaly as well.