Evaluation of mechanical properties of nanocrystalline alloys of Ti-Nb-Fe-Sn alloys system

Abstract

The synthesis of new Ti-based nanocrystalline alloys has been carried out because of their good engineering properties. These alloys are industrially important as structural and functional materials. Ti-based BMG alloys exhibit high strength (1800-2500 MPa), low elastic modulus (90-110 GPa) and, as expected, good corrosion resistance in various solutions. The Ti45Zr10Pd10Cu31Sn4 BMG discovered recently exhibits a good combination of high mechanical properties, corrosion resistance (chemical biocompatibility) and it is suitable for the production of alloys with high glass forming ability (GFA). The increasing of life expectance turns necessary the scientific and technologic development of biomaterials, mainly those with orthopedic application. This research aims the production, processing and optimization of properties in ² Ti-(Nb,Mo)-Fe-Sn alloys for fabrication of lower cost prosthesis for total hip replacement. The metallic alloys applied nowadays in Brazil have much higher elastic modulus (E) than the one of human bone (E = 10 to 30 GPa): Stainless Steel (200 GPa), Co-Cr Alloys (220 GPa), Ti-6Al-4V (110 GPa) and the search for alloys with enhanced mechanical and chemical biocompatibility is necessary.In this project are proposed new composition of Ti BMG alloys through combinations in the Ti-(Nb,Mo)-Fe system and the one which shows the best combination of properties will be submitted to different additions of tin (Sn) with the aim of optimize mechanical properties, avoid formation of metastable omega phase (É) together with a better biocompatibility (mechanical and chemical). It is desired a low elastic modulus of the alloy and the decrease in the melting point by the addition of eutectoid ²-stabilizing elements (Fe and Sn).The aim of the research project is the microstructure characterization of Titanium alloys of Ti-(Nb,Mo)-Fe-Sn system since the production of the alloy in an arc furnace, homogenization heat treatment, metalography, X-ray diffraction (XRD), optical (OM) and scanning electron microscopy (SEM) in order to obtain nanocrystalline composites, metastable and/or amorphous Ti alloys and the crystallization sequence study of equilibrium phases.