Yulia Zhukova

Manufacturing, Structure Control, and Functional Testing of Ti–Nb-Based SMA for Medical Application

This paper focuses on the development and characterization of Ni-free shape memory alloys, more specifically, Ti–Nb-based alloys for biomedical applications. It starts by describing the smelting technology used to produce small and medium size ingots of selected compositions. Thermomechanical treatments: structure interrelations are discussed next. Finally, the results of their mechanical, electrochemical, and in vitro cytotoxicity testing are presented to allow a general assessment of the mechanical, chemical, and biological aspects of compatibility of these alloys, and of the methods to control their functional properties.

A study of structure formation in Ti-Nb-Zr shape memory alloys for medical application

A study of structure formation in Ti-Nb-Zr shape memory alloys was carried out by means of transmission electron microscopy. After 450 °C annealing of cold-worked specimens a very high dislocation density (1011 cm−2) remained; after 600 °C annealing a mixed structure consisting of submicron sized grains and subgrains formed. Therefore, a nanosubgrained structure is expected to form after 500 – 550 °C annealing.

Martensitic Transformations and Mechanical and Corrosion Properties of Fe-Mn-Si Alloys for Biodegradable Medical Implants

The Fe-Mn-Si alloys are promising materials for biodegradable metallic implants for temporary healing process in the human body. In this study, three different compositions are considered (Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si, all in wt pct). The phase composition analysis by XRD reveals ε-martensite, α-martensite, and γ-austenite in various proportions depending on the manganese amount. The DSC study shows that the starting temperature of the martensitic transformation (Ms) of the alloys decreases when the manganese content increases (416 K, 401 K, and 323 K (143 °C, 128 °C, and 50 °C) for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively). Moreover, mechanical compression tests indicate that these alloys have a much lower Young’s modulus (E) than pure iron (220 GPa), i.e., 145, 133, and 118 GPa for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively. The corrosion behavior of the alloys is studied in Hank’s solution at 310 K (37 °C) using electrochemical experiments and weight loss measurements. The corrosion kinetics of the Fe-Mn-Si increases with the manganese content (0.48, 0.59, and 0.80 mm/year for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively). The alloy with the highest manganese content shows the most promising properties for biomedical applications as a biodegradable and biomechanically compatible implant material.