Eur. Phys. J. B (2015) 88: 169
https://doi.org/10.1140/epjb/e2015-60227-x

Regular Article

Temperature-induced phase transformation of Fe_1-xNi_x alloys: molecular-dynamics approach

Physics Department and Research Center OPTIMAS, University Kaiserslautern, Erwin-Schrödinger-Straße, 67663 Kaiserslautern, Germany

^a e-mail: urbassek@rhrk.uni-kl.de

Received: 21 March 2015
Received in final form: 8 May 2015
Published online: 1 July 2015

Abstract

Using molecular-dynamics simulation, we study the temperature induced bcc/fcc phase transformation of random Fe_1−xNi_x alloys in the concentration range of x ≤ 40 at%. The Meyer-Entel potential describes faithfully the decrease of the transition temperature with increasing Ni concentration. The austenite transformation proceeds by homogeneous nucleation and results in a fine-grained poly-crystalline structure. The transformation follows the Nishiyama-Wassermann orientation relationship. The martensite phase nucleates at the grain boundaries (heterogeneous nucleation). Even for the largest crystallite studied (2.75 × 10⁵ atoms) the back-transformation results in a single-crystalline grain containing only a small amount of defects. The morphological changes in the transformed material show no significant dependence on Ni content.