Reply to the two Comments, by A. Serra, D. J. Bacon and R. C. Pond, and by H. El Kadiri and C. Barrett on B. Li, H. El Kadiri and M.F. Horstemeyer “Extended zonal dislocations mediating twinning in titanium”

Serra, Bacon and Pond argue that, when the direction of the resolved shear stress on the twinning plane is reversed, the K 2 plane for twinning changes from (0 0 0 1) to , and the core structure, configuration and magnitude of the twinning dislocation change from b ±1 to b ±3. I contend that such behaviour has not been observed in any twinning mode in metals. A twinning mode should have a K 2 plane and the corresponding twinning dislocation that is structurally and energetically favourable and independent of the direction of the resolved shear stress. El Kadiri and Barrett echo the Comment by Serra et al. and argue that the one-layer twinning dislocation is an “artifact”, disregarding the fact that all the simulation results converge to one conclusion, i.e. the one-layer twinning dislocation is more favourable than the three-layer zonal dislocation, irrespective of the interatomic potentials used in the simulations. In this Reply, I seek to clarify such misinterpretations regarding twinning dislocation, twinning shear and shuffling in these Comments.