The Effect of Cold Swaging Deformation on the Microstructures and Mechanical Properties of a Novel Metastable β Type Ti-10Mo-6Zr-4Sn-3Nb Alloy for Biomedical Devices

This work investigated the microstructures, texture evolution, and mechanical properties of newly designed metastable beta type Ti-10Mo-6Zr-4Sn-3Nb (wt.%) alloys for biomedical devices, which were subjected to cold swaging deformation with reductions of 15-75%. With the increment in the reduction of swaging deformation, the grains are broken and gradually refined, and stress-induced martensite transformation takes place, resulting in the formation of the alpha" phase. Moreover, the {1 1 2} and {1 1 0} fibers turn into gamma-fiber {1 1 1} and alpha-fiber {1 1 2} with the increment in the swaging reduction. The alpha-fiber texture in particular, first weakens and then strengthens during cold deformation. Under the combined effect of sub-structures, grain refinement, and texture evolution, the strength of the alloy is gradually enhanced with the increment in the cold deformation reduction. The solution-treated alloy bar shows superior cold workability in the swaging process. The plasticity remains at a moderate level because the initial grains have not been completely broken at the beginning of cold swaging deformation. The elastic modulus of the alloy shows a downward trend with an increasing reduction, which is related to the dislocation multiplication, grain refinement, and grain orientation evolution during cold swaging deformation.