Workability Limits of Commercial Purity Titanium Subjected to Equal Channel Angular Pressing
Commercial purity Ti is an important candidate material for orthopedic and dental implants because of its high specific strength, good corrosion resistance and excellent biocompatibility. However, for biomedical applications as a replacement for Ti-6Al-4V alloy that is currently used, improvement in strength of CP Ti is necessary. This can be achieved by using severe plastic deformation (SPD) processes like equal channel angular pressing (ECAP) at warm working temperatures followed by conventional processing at room temperatures. This requires adequate workability after ECAP. In this study, the workability of CP Ti after warm ECAP has been investigated. Specimens of CP Ti, 17 mm in diameter, were extruded using processing route Bc through an ECAP die with an angle of 120◦ between the two intersecting channels and at a temperature of approximately 400oC. Workability testing was carried out using collar type compression specimens by upsetting the specimens between flat platens till the onset of cracking. Workability diagrams have been plotted as a function of axial and hoop strains at failure. The results show that processing by ECAP lead to only minor reductions in workability of CP Ti. The tensile strength is enhanced considerably by this process.
Yuri Estrin and Hans Jürgen Maier
G.V. P. Kumar and C. Uday, "Workability Limits of Commercial Purity Titanium Subjected to Equal Channel Angular Pressing", Materials Science Forum, Vols. 584-586, pp. 275-280, 2008