In the deadstop samples, we observed a bimodal distribution of WOP values near the skin, one representing sub-micron anisotropic structures (WOP ~0.5) and one representing isotropic ones (WOP ~0.0). Near the core, we observed a monomodal distribution indicating an isotropic structure with a WOP near 0.0 (Fig. and SI Fig. ). Between the core and skin, a transition from sub-micron anisotropic (bimodal) to isotropic (monomodal) takes place, with the position of the transition depending on the axial position along the cooling die. The further along the cooling die, the thinner the isotropic region, and the wider the region with sub-micron anisotropic structure.