Performance of Ti-15Mo alloy obtained by powder metallurgy route weakly alloyed with Fe/Cr elements

Abstract

[EN] Ti-15Mo alloy can be an excellent choice as a biomaterial for prostheses. This is due to the combination of good mechanical properties and biocompatibility. The Mo is a stabilizing element of the ß phase, which provides a smaller elastic modulus, reducing the risk of stress shielding that induces bone resorption. The present work shows the effect of minor additions of Fe or Cr on flexural fracture toughness in Ti-15Mo alloys obtained by Powder Metallurgy. The electrochemical results indicated that the Ti-15Mo-1Cr, showed greater resistance to corrosion, related to lower ß grain size, less porosity content compared to the other conditions. As the Ti-15Mo-1Fe and Ti-15Mo-3Fe presented more porosity in their microstructure, the saline composition inside the pores is different in concentration and thus makes diffusion difficult compared to other regular and more homogeneous zones. Besides, was verified the effect of the large grain size that decrease the corrosion resistance of the Ti-15Mo-3Cr, demonstrated two influences in the corrosion resistance, porosity and grain size. Toughness decreases with the addition of both elements, more pronounced with Fe than Cr. It is related with lower densification, higher porosity and greater proportion of phase ¿ in grain boundary due to the higher resistance of diffusion of Mo in Ti when Fe is present, which leads to failure by brittle fracture at lower shear stresses.