Coinciding significance of the crystallographic orientation and nanostructuring on the biocompatibility of TZNT-Ag1.5 alloy deformed by the cold rolling process

In this study, the simultaneous significance of the crystallographic texture and nanostructuring on the cytocompatibility of as-cast (Ti55Zr25Nb10Ta10)(98.5)-Ag-1.5 alloy (at. %, TZNT-Ag-1.5), subjected to cold rolling up to 90% reduction, along with the changes of Young's modulus and hardness under cold rolling were investigated. For this purpose, the as-cast and cold-rolled TZNT-Ag-1.5 alloy test specimens were analyzed by XRD, TEM, HRTEM, SEM, contact angle, nanoindentation, and OM techniques. Moreover, to evaluate the effect of severe cold deformation on the biocompatibility, MG-63 osteoblastic cell was cultured on the surface of 90% cold-rolled and as-cast test specimens of TZNT-Ag-1.5 alloy. The results showed that severe cold deformation was led to fast grain refinement of beta grains of the as-cast TZNT-Ag-1.5 alloy in the range of 50-100 nm. In addition to the nanostructuring, upon severe cold deformation, the -fiber (// normal direction) texture was formed and after 90% reduction, the (111)1 over bar 0> gamma(-fiber) component was strengthened. The micro-hardness and reduced Young's modulus are 235 +/- 5.29, 246 +/- 1.73, 271 +/- 4.0, and 283 +/- 6.25 (HV); and 73.725 +/- 1.70, 83.98 +/- 5.10, 81.26 +/- 6.55, and 88.66 +/- 7.16 (GPa) for TZNT-Ag-1.5 (as-cast), TZNT-Ag-1.5 (20%CR), TZNT-Ag-1.5 (50%CR), and TZNT-Ag-1.5 (90%CR) test specimens, respectively. Further, with increasing the cold deformation degree, the dislocation density of TZNT-Ag-1.5 alloy increased as this parameter is 2.79 x 10(15) (m(-2)) for the 90%CR test specimen. On the other hand, the values of the contact angle for the 90%CR test specimen (46.2 +/- 3.5 degrees) exhibit a higher hydrophilic and wettable surface as compared to the other studied test specimens. After 5 days of incubation, osteoblastic cells on the surface of the 90% cold-rolled TZNT-Ag-1.5 test specimens revealed significant differences in cell proliferation and differentiation as compared to the as-cast alloy test specimens and/or CP-Ti. Finally, because the maximum orientation intensities were generally <3, it was deduced that grain refinement rather than the crystallographic texture plays a significant role in improving the surface biocompatibility of the new TZNT-Ag-1.5 alloy.

Automated summary

This study investigated the impact of severe cold deformation on the crystallographic texture, nanostructuring, and cytocompatibility of (Ti55Zr25Nb10Ta10)(98.5)-Ag-1.5 alloy. Results showed that severe cold deformation resulted in grain refinement, formation of -fiber texture, and increased dislocation density, ultimately affecting the surface biocompatibility of the alloy.