Comparison of deformation twinning in tungsten and iron ballistic projectiles

We have observed dense Neumann bands in an iron explosively formed penetrator (EFP) and in directionally-oriented {[001], [011] and [111]} colunmar-grained tungsten long-rod penetrators. We have also correlated these bands with deformation twins in {211} planes using systematic bright-field and dark-field imaging utilizing identified twin reflections in the selected-area electron diffraction (SAED) patterns. These twins also seem to be associated with, or precursors to, dynamic recrystallization (DRX), which may also enhance or facilitate projectile flow phenomena that is especially prominent in depleted uranium (DU) as well as [001] single crystal tungsten rods.