Mechanical properties of cast Ti–Hf alloys

Abstract This study examined the mechanical properties of a series of Ti–Hf alloys. Titanium alloys with 10 to 40 mass % Hf were made with titanium and hafnium sponge in an argon–arc melting furnace. Specimens cast into magnesia‐based investment molds were tested for yield strength, tensile strength, percentage elongation, and modulus of elasticity. Vickers microhardness was determined at 25 to 600 μm from the cast surface. X‐ray diffractometry was also performed. Commercially pure Ti (CP Ti) and pure Ti prepared from titanium sponge were used as controls. The data ( n = 5) were analyzed with a one‐way ANOVA and the Student–Newman–Keuls test (α = 0.05). The diffraction peaks of all the metals matched those for α Ti; no β phase peaks were found. Alloys with Hf ≥ 25% had significantly ( p < 0.05) higher yield and tensile strength compared to the CP Ti and pure Ti. There were no significant differences ( p > 0.05) in elongation among all the Ti–Hf alloys and CP Ti, whereas the elongation of alloys with Hf ≥ 30% was significantly ( p < 0.05) lower than that of the pure Ti. The cast Ti–Hf alloys tested can be considered viable alternatives to CP Ti because they were stronger than CP Ti and had similar elongation. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 362–367, 2005