Atomistic simulations of tungsten nanotubes under uniform tensile loading

Metallic nanotubes (NTs) have gained much attention in recent years due to their exciting potential to be just as strong or even stronger than their heavier counterparts, nanowires (NWs), with the same outer radius. Unlike NWs, NTs have inner wall diameter and wall thickness parameters that can be engineered to provide advantage in structural materials design. In this work, molecular dynamics is used to quantify the combined effects of NT specific dimensions, outer radius and wall thickness, on the tensile strength of single crystalline tungsten NTs at room temperature. Uniaxial tensile simulations are carried out for three different crystallographic orientations along the NT axis-two known as brittle orientations and one as ductile orientation. For these three orientations, the strength of NTs can be made higher than NWs, for the same outer radius, as the wall thickness decreases. The calculations indicate that even for the brittle orientations, NTs can be engineered to be more ductile by tuning the outer radius and the wall thickness.