Design and characterization of Ti6Al4V/20CoCrMo-highly porous Ti6Al4V biomedical bilayer processed by powder metallurgy

The aim of this work was to develop a Ti6Al4V/20CoCrMo-highly porous Ti6Al4V bilayer for biomedical applications. Conventional powder metallurgy technique, with semi-solid state sintering as consolidation step, was employed to fabricate samples with a compact top layer and a porous bottom layer to better mimic natural bone. The densification behavior of the bilayer specimen was studied by dilatometry and the resulting microstructure was observed by scan electron microscopy (SEM) and computed microtomography (CMT), while the mechanical properties and corrosion resistance were evaluated by compression and potentiodynamic tests, respectively. The results indicate that bilayer samples without cracks were obtained at the interface which has no negative impact on the densification. Permeability values of the highly porous layer were in the lower range of those of human bones. The compression behavior is dictated by the highly porous Ti6Al4V layer. Additionally, the corrosion resistance of Ti6Al4V/20CoCrMo is better than that of Ti6Al4V, which improves the performance of the bilayer sample. This work provides an insight into the important aspects of a bilayer fabrication by powder metallurgy and properties of Ti6Al4V/20CoCrMo-highly porous Ti6Al4V structure, which can potentially benefit the production of customized implants with improved wear performance and increased in vivo lifetime.

Automated summary

This study developed a Ti6Al4V/20CoCrMo highly porous Ti6Al4V bilayer structure using powder metallurgy, showing good densification and ability to mimic natural bone tissue. The bilayer samples had no cracks at the interface, and the permeability of the highly porous layer was similar to that of human bones.