Laser cladding of high energy ball milled powder of nanocrystalline Ti-(Nb,Mo)-Fe-Sn alloys

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 Ti-Fe-Co and Ti-Fe-Sn nanocrystalline alloys discovered recently exhibits a good combination of high mechanical properties and are suitable for the production of Ti alloys with good corrosion resistance and low Young (elasticity) modulus (E). 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.The preparation of the powders of the Ti-(Nb,Mo)-Fe-Sn alloys will be performed through high energy ball milling (HEBM) process in a ZOZ mill. The work will be developed from samples containing a few hundred grams (200 to 500 g). After preparing the samples in sufficient quantity thereof will be characterized and the other part will undergo subsequent processing. The laser cladded coatings of the powders in titanium substrate will be realized in the mechanical engineering faculty at the State University of Campinas (UNICAMP). The whole procedure will be joined by student. It will be varied the laser parameters, power (W) and laser scanning speed (mm/s). The individual and overlapping tracks will be submitted through microstructural characterization (optical and electron microscopy, SEM) and Vickers hardness measurements.In this renovation project of the scientific initiation (IC) grant proposal nanocrystalline alloys are selected (from the previous 1st year of project) Ti66Fe20Nb8Sn6 and Ti64Fe22Mo8Sn6 (%at), in order to produce coatings on titanium substrates through Laser Cladding powder obtained by High Energy Ball Milling (HEBM). (AU)