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MM: Fachverband Metall- und Materialphysik

MM 39: Topical session (Symposium EPS and MM): Mechanical Properties at Small Scales

MM 39.3: Talk

Wednesday, March 14, 2018, 15:45–16:00, H 0107

Tensorial elastic properties and thermodynamic stability of Σ5(210) grain-boundary interface states in Ni₃Al — •Martin Friák^1,2, Monika Všianská^1,3,4, David Holec⁵, and Mojmír Šob^3,1,4 — ¹Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Brno, Czech Republic — ²Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic — ³Central European Institute of Technology, CEITEC MU, Masaryk University, Brno, Czech Republic — ⁴Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic — ⁵Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Leoben, Austria

Grain boundaries (GBs) are among the most important defects in solids and their properties are crucial for many materials properties including their (in)stability. We calculate and analyze (tensorial) anisotropic elastic properties of interface states associated with GBs in Ni₃Al. Selecting the Σ5(210) GBs as a case study, we address the mechanical stability of the GB interface states by checking elasticity-based Born stability criteria. One of critically important elastic constants, C₅₅, is found three times lower than in the bulk. Having the complete elastic tensor of Σ5(210) GB states we combine a Green’s-function based homogenization techniques and an approximative approach to the Debye model to compare thermodynamic properties of a perfect Ni₃Al bulk and the Σ5(210) GB states. A significant reduction of the melting temperature is predicted (see IOP Conf. Series: Mat. Sci. Eng. 219 (2017) 012019 doi:10.1088/1757-899X/219/1/012019).