|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Computational Design and Simulation of Materials (CDSM 2018): Atomistic Simulations
||Phase Stability and Chemical Composition of Nanoprecipitates: A First Principles Study for the Example of Kappa Carbides
||Tilmann Hickel, Poulumi Dey, Biswanath Dutta, Martin Friák, Joerg Neugebauer
|On-Site Speaker (Planned)
We combine density functional theory with the concept of chemical potentials to simulate the interplay between nanoprecipitate and matrix phase. This combination provides a physically intuitive tool that allows one to describe continuous changes of the composition and resulting configurational entropy, though the actual calculations are limited to finite-size supercells and discrete concentrations. For the equalization of the chemical potentials of the C atoms between carbides and the matrix a constrained paraequilibrium is assumed. In addition to the chemistry, the minimization of the total Gibbs energy also takes the optimum coherent lattice parameter of matrix and precipitates into account. This new concept is applied to nano-sized kappa carbides (Fe,Mn)3AlC, one of the most important precipitate phases in Fe-Mn-Al-C steels. The resulting chemical composition and lattice constants compare well with accurate experimental data from atom probe tomography (APT) and X-ray diffraction.
||Planned: Supplemental Proceedings volume