Mechanical properties of iron filled carbon nanotubes: Numerical simulations

Abstract

The deformation process of Fe encapsulated in a carbon nanotube (CNT) is investigated by means of classical molecular dynamics. The [100], [110], and [111] Fe crystal orientations parallel to the CNT symmetry axis, as well as the temperature dependence, are studied. The system encompasses approximately 80 000 atoms. While crystal orientation and temperature determine the system's response, the results are almost independent of the strain rate that is applied. This behavior is only slightly modified by the Fe encapsulation in the CNT. The principal energy release mechanism is the generation of dislocations and twin boundaries, at low and intermediate temperatures (T <= 600K). The dislocations and twin boundaries interact, but do not interlock. For large temperatures (T similar to 1000K), a different reaction to deformation sets in, and no elastic response of the Fe-CNT system is observed.