Mechanical, corrosion, nanotribological, and biocompatibility properties of equal channel angular pressed Ti-28Nb-35.4Zr alloys for biomedical applications

This study systematically investigated the effect of equal channel angular pressing (ECAP) on the mi-crostructure, mechanical, corrosion, nano-tribological properties and biocompatibility of a newly devel-oped fi Ti-28Nb-35.4Zr (hereafter denoted TNZ) alloy. Results indicated that ECAP of the fi TNZ alloy re-fined its microstructure by forming ultrafine grains without causing stress-induced phase transformation, leading to formation of a single fi phase. The ECAP-processed TNZ alloy exhibited a compressive yield strength of 960 MPa, and high plastic deformation capacity without fracturing under compression loads. Potentiodynamic polarization tests revealed the higher tendency of ECAP-processed TNZ alloys to form passive oxide films on its surface, which exhibited a lower corrosion rate (0.44 +/- 0.07 mu m/y) in Hanks' balanced salt solution compared to its as-cast counterpart (0.71 +/- 0.10 mu m/y). Nanotribological testing also revealed higher resistance of the ECAP-processed TNZ alloy to abrasion, wear and scratching, when com-pared to its as-cast counterpart. Cytocompatibility and cell adhesion assessments of the ECAP-processed TNZ alloys showed a high viability (111%) of human osteoblast-like SaOS2 cells after 7 d of culturing. Moreover, the ECAP-processed TNZ alloy promoted adhesion and spreading of SaOS2 cells, which exhib-ited growth and proliferation on alloy surfaces. In summary, significantly enhanced mechanical, corrosion, and biological properties of ECAP-processed TNZ alloy advocate its suitability for load-bearing implant applications.