Molecular dynamics modeling of cavity strengthening in irradiated iron

Abstract

One of the most important problems in the field of nuclear industry is the relationship between irradiation-induced damage and the resulting induced mechanical response of the target metal and in particular ferritic base steels. In this work molecular dynamics simulation is used to simulate the nanoscale interaction between a moving dislocation and a defect, such as a cavity, as void or He bubble. The stress-strain curves are obtained under imposed strain rate condition using the atomic potentials based on the Fe potential of Ackland et al. 1997 for a void and He bubble as a function of He content and temperature. It appears that a 2 nm void is a stronger obstacle than a He bubble at low He contents, whereas at high He contents, the He bubble becomes a stronger obstacle. With increasing temperature the escape stress decreases and at the same time there is increasing degeneracy in the type of interaction.

Effect of interatomic potential on the behavior of dislocation-defect interaction simulation in α-Fe

“…The release stress is decreasing with increasing of temperature. This behavior is comparable to the one obtained with the Ackland potential [26]. Fig.…”

Dislocation–void interaction in Fe: A comparison between molecular dynamics and dislocation dynamics

“…Presence of He bubble may weaken or strengthen the material depending on the density of He. We have shown that in pure iron a low content He bubble is a weaker obstacle than a void, whereas a high density He bubble is a stronger obstacle than a void [7].…”

“…This seems to hinder the dislocation release from the void. It should be noted that the obstacle strength depends mainly on exit mechanisms, which relate to the mobility of the screw parts of the interacting dislocation [7].…”

From materials development to their test in IFMIF: an overview

“…It appears that these nano-sized defects act as strong obstacles to the propagation of mobile dislocations, the strongest being the voids, then the helium bubbles (figure 4, middle) [26][27][28], and the weakest the chromium precipitates [29]. When chromium is placed randomly in substitution in iron [30], it significantly hardens the matrix, following a classical behaviour of solid solution hardening.…”