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Mechanical properties of cast Ti-Hf alloys

Objective: This study examined the mechanical properties of a series of Ti-Hf alloys. Methods: Titanium alloys with 10-40 mass% Hf were made with sponge Ti (Toho Titanium, Japan) and sponge Hf (Toho Tec, Japan) in an argon-arc melting furnace. Molds were prepared using a dumbbell-shaped plastic pattern (gauge length: 20mm, 2.9mm diameter) with magnesia investment material (Selevest CB, Selec, Japan). Cast specimens were tested for yield strength (YS), tensile strength (TS), percent elongation (El) and modulus of elasticity (ME) at a crosshead speed of 0.25 mm/min. Vickers hardness was determined at 25-600 mm from the cast surface. X-ray diffractometry was also performed. Commercially pure Ti (CP Ti) and pure sponge Ti were used as controls. Data (n=5) were analyzed with a one-way ANOVA and the Student-Newman-Keuls test (a=0.05) [mean (SD)].

 

10Hf

20Hf

25Hf

30Hf

35Hf

40Hf

Pure Ti

CP Ti

YS(MPa)

437(30)

480(19)

500(24)

528(23)

535(37)

579(24)

374(14)

416(32)

TS(MPa)

508(31)

567(9)

607(12)

642(12)

650(17)

692(12)

440(19)

532(7)

El (%)

10.9(2.2)

9.3(1.1)

9.6(1.0)

7.9(1.4)

7.2(2.1)

5.7(2.2)

13.1(1.4)

7.1(0.8)

Results: The diffraction peaks of all the metals tested matched those for a Ti; no b phase peaks were found. Alloys with Hf³25% had significantly (p<0.05) higher YS and TS compared to CP Ti. There were no significant differences (p>0.05) in El among all the Ti-Hf alloys and CP Ti, whereas the El of alloys with Hf³30% was significantly (p<0.05) lower than pure Ti. The ME of all metals tested (105-127GPa) were not significantly different (p>0.05). Conclusion: The cast Ti-Hf alloys tested can be considered viable alternatives to CP Ti since they were stronger than CP Ti and their elongation was similar. This study was partially funded by NIH/NIDCR grant DE 11787.

 

 


Division: IADR/AADR/CADR General Session
Meeting: 2004 IADR/AADR/CADR General Session (Honolulu, Hawaii)
Location: Honolulu, Hawaii
Year: 2004
Final Presentation ID: 3973
Abstract Category|Abstract Category(s): Dental Materials: VII - Others-Metallic
Authors
  • Sato, Hideki  ( Tohoku University Graduate School of Dentistry, Sendai, N/A, Japan )
  • Kikuchi, Masafumi  ( Tohoku University Graduate School of Dentistry, Sendai, N/A, Japan )
  • Okuno, Osamu  ( Tohoku University Graduate School of Dentistry, Sendai, N/A, Japan )
  • Komatsu, Masashi  ( Tohoku University Graduate School of Dentistry, Sendai, N/A, Japan )
  • Okabe, Toru  ( Baylor College of Dentistry, Dallas, TX, USA )
    • SESSION INFORMATION
    Oral Session
    Metals: Hardness & Wear
    03/13/2004