Competition between full slip and twinning in BCC-Fe: Effect of preloaded stress and temperature

Slip or twinning is one of the fundamental questions in the deformation studies of metals and alloys. Internal parameters such as generalized stacking fault energy and size and external parameters such as pressure, strain rate, and temperature influence the competition between the full slip and twinning, thus dictating the predominance of one mechanism over the other. In the present investigation, we studied the influence of preloaded stress and temperature on the deformation behavior of BCC-Fe nanowires using molecular dynamics simulations and theoretical analysis. Based on detailed investigations into the energetics associated with slip and twinning, we observed that twinning is the preferred deformation mechanism in BCC-Fe. However, this has been modified by preloaded stresses applied in normal, transverse, and both directions on the nanowire. We observed a slip on {110}, on {112}, and even on {123} planes. The temperature did not alter the inherent twinning nature but linearly decreased the various fault energies.