Eur. Phys. J. Special Topics 227, 1559-1574 (2019)
https://doi.org/10.1140/epjst/e2019-800154-6

Regular Article

Precipitation, planar defects and dislocations in alloys: Simulations on Ni₃Si and Ni₃Al precipitates

Institut für Materialprüfung, Werkstoffkunde und Festigkeitslehre (IMWF), Universität Stuttgart, Stuttgart, Germany

^a e-mail: stephen.hocker@imwf.uni-stuttgart.de

Received: 27 September 2018
Received in final form: 6 November 2018
Published online: 8 March 2019

Abstract

We present simulations of the formation of Ni₃Si precipitates using a combination of molecular dynamics (MD) and the Metropolis Monte Carlo (MMC) method. Applying this technique to a Ni-Si solid solution in Cu matrix leads to Ni₃Si precipitates with L1₂ structure as observed in experiments. Since L1₂ structured precipitates are most relevant for precipitation strengthening of several alloys, we focus on planar defects and dislocations in Ni₃Si and Ni₃Al. Ab initio calculations of the generalised stacking fault energies of Ni₃Si presented in our previous work [S. Hocker, H. Lipp, E. Eisfeld, S. Schmauder, J. Roth, J. Chem. Phys. 149, 024701 (2018)] revealed that the complex stacking fault is not stable and the inflection point as well as the minimum corresponding to the antiphase boundary is shifted. In this study it is shown that this behaviour can be understood from the analysis of charge densities. Furthermore, the consequences on dislocations in Ni₃Si and Ni₃Al are discussed and interactions of edge dislocations with Ni₃Si and Ni₃Al precipitates are simulated.