Molecular dynamics study of strengthening by nanometric void and Cr alloying in Fe

Ferritic steels are the main candidates for the structural components of future fusion reactors. Because of the complexity of their structure, most of the simulation works are focused on the base phase of these materials such as alpha-Fe or Fe–Cr alloy. In this work molecular dynamics (MD) simulation is used to investigate the influence of chromium on the plasticity of bcc Fe–Cr alloy. Recent interatomic potentials for the Fe–Fe interactions are compared, namely Chiesa 2009 and Malerba 2010, with a comparison to Ackland 1997, Mendelev 2003 and Ackland 2004, widely used in this field. For the Fe–Cr system the potentials of Ackland 2004 for Fe–Fe and of Olsson 2005 for Fe–Cr and Cr–Cr interactions are used. Firstly, the recent Fe–Fe interatomic potentials are assessed by studying the interaction of the edge dislocation with a 2nm void at 10K. Secondly, the impact of Cr in Fe on the mobility of an edge dislocation for contents between 0 and 100at.% is studied. It appears that its glide stress increases with Cr content up to about 60at.%, and then decreases. The high flow stress observed at 60at.% Cr does not relate to Cr intrinsic mechanical properties, but to the induced lattice distortion.