Large recovery of six-fold twinned nanowires of α-Fe

Six-fold twinned nanowires sustain very large twists under torsion. The twist is generated by mobile twin boundaries. In contrast, torsion in un-twinned nanowires is carried by dislocations and leads to failure for small torsion angles. The twisted, twinned nanowire can be totally “untwisted” by the reverse motion of twin boundaries, leading to huge pseudo-elasticity. The movement of twin boundaries and dislocations is non-smooth. It progresses by jerks and avalanches. Molecular dynamics simulations show that twin boundary jerks are power law distributed and the size exponent is compatible with mean field theory.