Impact of Rotary Forging on the Structure, Texture, and Properties of Rods Made of a Biocompatible β-alloy Ti-39Nb-7Zr

Abstract

In this study, we examined the structure, texture, and mechanical properties of β-alloy Ti-39Nb-7Zr rods following intensive plastic deformation through rotary forging (RF). Finite element method (FEM) simulations revealed an uneven stress distribution within the rods, characterized by predominantly tensile stresses in the core and compressive stresses at the surface. Statistical analysis of orientation microscopy data indicated a microstructural gradient: both the thickness of deformed grains and the size of recrystallized grains decreased from the core to the surface, while the proportion of recrystallized grains increased. The RF process induced a gradient texture, with distinct grain orientations in the central and near-surface areas. An increase in hardness in the near-surface layers was attributed to grain refinement. Taylor factor calculations showed a minor effect of texture on the mechanical properties. The elastic modulus across the rod section remained consistent at 75 ± 1 GPa, suggesting that surface hardening was achieved without altering elastic properties.