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MM: Fachverband Metall- und Materialphysik

MM 39: Structural Materials (Steels, light-weight materials, high-temperature materials)

MM 39.3: Vortrag

Donnerstag, 4. April 2019, 15:30–15:45, H45

Theoretical modeling of interstitial carbon impurities in Fe-Mn paramagnetic alloys — Alena Ponomareva¹, Bobur Mukhamedov¹, and •Igor Abrikosov^1,2 — ¹Materials Modeling and Development Laboratory, National University of Science and Technology "MISIS", 119049 Moscow, Russia — ²Department of Physics, Chemistry, and Biology (IFM), Linköpings University, SE-58183 Linköping, Sweden,

We present a generalization of a model that takes into account the magnetic disorder of paramagnetic host with interstitial point defects [1] towards the case of the alloys. In the framework of disordered local moment picture combined with magnetic sampling method, we calculate a solution enthalpy of carbon impurity in the paramagnetic fcc Fe-Mn steels. First, we use the magnetic special quasirandom structure (M-SQS) method for simulation of the paramagnetic state in Fe-Mn alloys without impurity. Here, Fe and Mn atoms are randomly distributed at the sites of a supercell. Next, to calculate the energies for various magnetic realizations around the interstitial carbon impurity, we move the position of the impurity within the SQS. Our calculations show that in alloys containing about 20 at. % Mn, the solution enthalpy of carbon reduces compared to the pure fcc-Fe. By analyzing the local and global effects of impurity on the properties of the matrix, we discuss various factors that could increase the carbon solubility in high-manganese austenitic steels.

[1] A. V. Ponomareva, Yu. N. Gornostyrev, and I. A. Abrikosov, Phys. Rev. B 90, 014439 (2014).