Determining the elasticity of materials employing quantum-mechanical approaches: from the electronic ground state to the limits of materials stability
M. Friák, T. Hickel, F. Körmann, A. Udyansky, A. Dick, J. von Pezold, D. Ma, O. Kim, W. A. Counts, M. Sob, T. Gebhardt, D. Music, J. Schneider, D. Raabe, J. Neugebauer.
Steel Research International, 82, 86-100, (2011)
Quantum-mechanical (so-called ab initio) calculations have achieved considerable reliability in predicting physical and chemical properties and phenomena. Due to their reliability they are becoming increasingly useful when designing new alloys or revealing the origin of phenomena in existing materials, also because these calculations are able to accurately predict basic material properties without experimental input. Due to the universal validity of fundamental quantum mechanics, not only ground-state properties, but also materials responses to external parameters can reliably be determined. The focus of the present paper is on ab initio approaches to the elasticity of materials. First, the methodology to determine single-crystalline elastic constants and polycrystalline moduli of ordered compounds as well as disordered alloys is introduced. In a second part, the methodology is applied on a-Fe, with a main focus on (i) investigating the inﬂuence of magnetism on its elasticity and phase stability and (ii) simulating extreme loading conditions that go up to the theoretical tensile strength limits and beyond.
Keyword(s): ab initio; elasticity, magnetism; stability; strength