Development and characterization of Ti-20Zr-Mo Alloys for

Development and characterization of Ti-20Zr-Mo Alloys for biomedical
applications
Pedro Akira Bazaglia Kuroda(*), Carlos Roberto Grandini.
UNESP – Univ Estadual Paulista, Laboratório de Anelasticidade e Biomateriais, Bauru, SP
IBTN – Institute of Biomaterials, Tribocorrosion and Nanomedicine – Brazilian Branch
Titanium has an allotropic transformation around 883 °C. Below this temperature, the
crystalline structure is hexagonal close-packed (α phase), changing to body-centered cubic (β phase)
[1]. Zirconium has the same allotropic transformation around 862 °C [2]. Molybdenum has bodycentered cubic structure, being a strong β-stabilizer for the formation of titanium alloys [3].
This study aims the development of Ti-20wt%Zr-xMo ( x = 0, 2.5, 5, 7.5 and 10wt% ) alloys
to be used in biomedical applications. The samples were prepared in an arc-melting furnace. After
melting, the materials went through heat treatment for homogeneity, hot rolling and a new heat
treatment for stress relief. The samples were characterized by density measurements, x-ray diffraction
with subsequent refinement by the Rietveld method, optical and SEM microscopy. The mechanical
properties were analyzed by Vickers microhardness and dynamic elasticity modulus. X-ray
measurements and Rietveld analysis revealed the presence of α’ phase without molybdenum, α’+ α”
phases with 2.5wt% of molybdenum, α”+β phases with 5, 7.5 and 10wt% of molybdenum. These
results were corroborated by microscopy results, with a microstructure composed of grains of β phase
and lamellae and needles of the α'' and α” phase in the region intra-grain. The hardness of the alloy
was higher than the commercially pure titanium, due to the action of zirconium and molybdenum as
hardening agents. The samples have a smaller elasticity modulus than the commercially pure titanium.
Acknowledgments:
CAPES, CNPq, FAPESP,
References:
[1] M. Geetha et al.. Progress in Materials Science, v. 54, p. 397-425, 2009.
[2] X.B. Chen et al.. Advanced Materials Resarch.v. 15–17, p. 89–94, 2007.
[3] C. Leyens; M. Peters, Titanium and titanium alloys, Wiley-VHC: Weinheim, 2003