Tensile strain induced texture evolution in a Ni–Mo alloy with extremely fine nanotwinned columnar grains

Abstract

In the present paper, plastic deformation in an electrodeposited nanotwinned columnar grained Ni–Mo film with an extremely fine columnar grain size of 8 ± 1.7 nm and a twin thickness of 1.3 ± 0.5 nm was investigated via uniaxial micro-tensile tests at room temperature. We found significant detwinning and an evident texture evolution from a randomly-oriented in-plane fiber texture to a highly-oriented out-of-plane texture in the alloy upon tensile straining when tensile direction was oriented in parallel to the twinning plane. Interface energy minimization characterized by the substitution of high angle grain boundaries by low angle grain boundaries and incoherent twin boundaries constitutes the driving force of the texture evolution. Tensile plastic deformation can be attributed to the activity of threading dislocations, which not only contributes to a high yield strength of 2.11 GPa, but also results in in-plane lattice rotation with noticeable deformability.