Hierarchical nanotwins in single-crystal-like Nickel with high strength and corrosion resistance produced via a hybrid technique

High-density growth nanotwins enable high-strength and good ductility in metallic materials. However, twinning propensity is greatly reduced in metals with high stacking fault energy. Here we adopted a hybrid technique coupled with template-directed heteroepitaxial growth method to fabricate single-crystal-like, nanotwinned (nt) Ni with anomalously high-density nanoscale twins. The nt Ni primarily contains hierarchical twin structures that consist of coherent and incoherent twin boundary (CTB and ITB) segments with few conventional grain boundaries. In situ compression studies show the nt Ni has a high flow strength of ~ 2 GPa and good deformability. Moreover, the nt Ni offers superb corrosion behavior due to the unique twin structure in comparison to coarse grained and nanocrystalline counterparts. The hybrid technique opens the door for the fabrication of a wide variety of single-crystal-like nt metals with unique mechanical and chemical properties.