Martensitic transformation temperature modification of Fe-SMA for efficient medical implants

Abstract

Nickel-Titanium alloys or Nitinol shape memory alloys have applications in various fields like biomedical, agriculture, pharmaceutical, civil, and mechanical engineering. Ferrous-based shape memory alloys (Fe-SMAs) do not possess excellent properties like that of Nitinol. In recent times, Fe-SMAs have been under consideration in the research field to enhance their shape memory properties because of their cost-effectiveness, corrosion resistance, biocompatibility, and high mechanical strength. Fe-SMAs are limited in their applications in the human body due to high austenite start temperature () even though they are biocompatible and being considered for temporary biodegradable implant applications. Several factors affect the phase transformation temperature of Fe-SMA, like alloy composition and heat treatment conditions. Some of the techniques that are useful to reduce the are quenching, solid solution treatment, ternary element addition, alloying, and thermal-mechanical treatment. In this study, the quenching with brine solution is used to reduce of Fe-15Mn-10 Cr-8Ni-4Si (wt. %). The phase transformation is observed using Differential Scanning Calorimetry (DSC). The best result from experimentation of all the samples collected as reduced from 93oC to 39.02oC which is very close to the temperature of the human body. The results of this study exhibit significant potential for advancement in the application of Fe-SMAs in the biomedical field for permanent implants in cardiovascular and orthopaedic applications.