Thixoforming of titanium alloys: application to Ti-Cu, Ti-Fe and Ti-Co systems

Abstract

The use of titanium and its alloys as structural materials has grown steadily in the last few years, which is due to the interesting combination of mechanical, chemical, physical and biomedical properties of this metal. The most intense increase in the industrial consumption of titanium is strongly limited by its cost, which is related not only to the difficulties of its refining, but mainly to its high processing cost. The processing of titanium in order to obtain specific geometries is a high complexity task, which increases the cost of the final product. A very innovative approach to process titanium alloys is the use of thixoforming techniques. The goal of this research project is to examine the thixoformability of alloys in the Ti-Cu, Ti-Fe and Ti-Co systems. This objective will be achieved through: (a) assessment of the Ti-Cu, Ti-Fe and Ti-Co systems and selection of compositions with potential for thixoforming, (b) production of selected alloys and experimental evaluation of working temperatures, (c) morphological evaluation in semisolid state, (d) evaluation of the viscous behavior and finally (e) evaluation of the mechanical behavior of the thixoformed material. The samples will be produced by arc melting and thixoprocessed in an equipment comprising a stainless steel chamber which operates under inert atmosphere. Inside this chamber, samples will be heated by using electromagnetic induction. The characterization of the samples will involve thermal analysis techniques, X-ray diffraction, optical and electron microscopy and mechanical testing. At the end of this research it will be possible to diagnose the feasibility of thixoforming titanium alloys. (AU)