This study presents a methodology to fabricate Ti6Al4V cylindrical compacts with a highly porous core and dense shell with the aim to mimic the bone microstructure. Compacts with different core diameters were obtained via conventional pressing and sintering. Large pores were created with the aid of pore formers. Dilatometry was used to determine the sintering kinetics, while X-ray computed tomography was used for characterization. Also, the permeability was evaluated on the 3D microstructure, and the mechanical strength was evaluated via compression tests. The results indicated that sintering was constrained by the different densification rates of the porous and dense layers. However, defect-free compacts were obtained due to neck bonding between the Ti6Al4V particles. Large pores were located in the designed core with a similar pore size distribution. The permeability increased following a power law as a function of the pore volume fraction. The porous core drove the stiffness of the bilayer components, while the combination of both layers increased their strength. The bilayer materials showed permeability (1.36 × 10⁻¹⁰ m²), mechanical properties (E = 6.83 GPa and σ_y = 299 MPa), and admissible strain (σ_y/E = 43 × 10⁻³) similar to those of human bones.

The present study shows the effect of Nb on a Ti matrix to fabricate composites via the conventional powder metallurgy for medical applications. Ti powder mixture compacts with different Nb contents were obtained from the conventional pressing and sintering technique. The sintering behavior was evaluated using the dilatometry technique, and the microstructure was studied using scanning electron microscopy (SEM) and X-ray diffraction (XDR). The mechanical properties were obtained from simple compression tests, and the corrosion resistance was determined from a standard three-electrode arrangement in Hank’s solution. The results showed that the Nb in the Ti matrix limits the evolution of sintering depending on the Nb content. Nb slightly accelerates the phase transition temperature. The microstructure and X-rays revealed that biphasic α + β-Ti structures can be obtained, in addition to retaining the β-Ti phase and forming the martensitic phases α′ and α″ of Ti. Likewise, the mechanical behavior showed a Young’s modulus of 10–45 GPa, which is close to that reported for human bones. Furthermore, the circuit analysis revealed that the Ti-Nb sintered systems were conditioned by the surface oxide layer and that the oxide layer formed within the residual pores of the sintering process. Finally, it was demonstrated that adding Nb to the Ti matrix increases the corrosion resistance and that contents close to 15 wt.% of this element have the best results.

The present work is focused on developing Ti-xTa porous alloys processed by the space holder method and solid-state sintering. The volume fraction of Ta ranged between 20 and 30 wt.%. The sintering kinetics was evaluated by dilatometry tests. Sintered materials were characterized by SEM, XRD and computed tomography. Porosity features and permeability were determined from 3D images, and their mechanical properties were evaluated from microhardness and compression tests. The sintering behavior and the final microstructure are driven by the Ta diffusion into the Ti, slowing down the densification and modifying the transition temperature of α-to-β. Due to β-stabilization, martensite α′ was obtained after sintering. Mechanical properties are reduced because of the β-stabilization and pore addition, being predominantly the pore effect. Permeability depended on the pore characteristics, finding values close to the human bones. It was concluded that powder metallurgy generates highly TixTa alloys with a combination of α, β and α′ Ti phases as well as remaining Ta particles that are beneficial to improve the biocompatibility and osseointegration of such materials. Being the Ti25Ta40salt alloy the most suitable for orthopedic implants because of its characteristics and properties.

This works proposes a methodology for fabricating materials with specific characteristics mimicking human bones. A Ti64 alloy powder was used as the base material and it was mixed with Ag, Ta, TiN and salt particles to obtain different features. A hip-bone like component was fabricated, including a highly porous core of Ti64/25Ta/5Ag and a compact outer shell of Ti64/5Ag that is supposed to improve corrosion and osseointegration. Besides, a harder cover surface in Ti64/10TiN composite should increase the wear resistance. The green component was sintered at 1260°C in argon. Its Young’s modulus was close to the one of bones due to the added porosity, which also provided a permeability close to the one reported for trabecular bones. Tribocorrosion behaviour in simulated body fluid was improved by TiN addition. In conclusion, the proposed processing route was able to produce complex components fulfilling specific features required for human bone replacement.