Alloying titanium and tantalum by cold crucible levitation melting (CCLM) furnace

Recently, titanium alloys have been studied as implant materials for dental and orthopedic surgery. Titanium alloys have distinguished characteristics of biocompatibility, corrosion resistance and mechanical properties. Havin g non-poisonous character to a living body, Ta, Zr and Nb have been used fo r addition to titanium alloys, which are free of vanadium and aluminum. It is well-known that titanium and tantalum are difficult metals to alloy in u sual furnaces as these are very reactive metals, having great differences i n melting point anti specific gravity. To produce an alloy of titanium and tantalum, cold crucible levitation melting (CCLM) is effective in obtaining a uniform composition. Notable features of CCLM are that it can (1) melt m etals with a high melting point, (2) create an alloy of uniform composition with a strong stirring effect by an electromagnetic force and (3) allow me tals to be melted without contamination. We have melted 850 g of titanium a nd 150 g of tantalum by a CCLM furnace and have successfully made 1.0 kg of uniform composite Ti-15wt.% Ta alloy. It is noteworthy that the alloy was produced from pure base metals which were not alloyed beforehand and was ma de by a single melting (no re-melting) process. (C) 2000 Elsevier Science S .A. All rights reserved.