MICROSTRUCTURE AND MECHANICAL PROPERTIES OF NANOSTRUCTURED Ti-22Nb-10Zr COATINGS

The design of implants and functional prostheses requires superficial modifications that promote fast and lasting osseointegration. Magnetron sputtering enables to design nanostructured and textured β-Ti rich Ti22Nb-10Zr (wt.%) coatings with variable mechanical properties (hardness and Young’s modulus). Depending on the magnitude of the bias voltage used during deposition of the coating, martensitic transformation from the unstable β (bcc) to α” (orthorhombic) phase is activated. This transformation induces compressive residual stresses modifying the tensile strength, hardness and Young's modulus. The residual stresses were measured by nanoindentation, the microstructure and phase evolution were characterized by X-ray diffraction. The spatial phase distribution was determined by transmission electron microscopy. The calculated real hardness increases from 2.1 to 4.1 GPa as the bias voltage is increased from 0 to -148 V. The calculus confirms that the coating has a non-linear elastic behavior.