Processing of Porous Β-Type Ti74nb26 Alloys for Biomedical Applications

Abstract

Ti74Nb26 alloys with porosities in the range of 45-68% were produced employing Mg space holder technique combined with hot pressing using elemental Ti, Nb and Mg powders. Powder mixtures were hot pressed at 600 degrees C (below the melting point of Mg, 650 degrees C) for 1 h under a constant pressure of 50 MPa and flowing argon gas. After hot pressing samples were sintered in a vertical furnace at 1200 degrees C (above the boiling temperature of Mg, 1090 degrees C) for 4 h under flowing inert argon gas atmosphere. Evaporation and removal of Mg particles from the samples were carried out during sintering simultaneously. X-ray diffraction and scanning electron microscopy analysis revealed that beta phase was the main phase in the microstructure of all the samples. A small amount of a and undissolved pure Nb were also observed. Room temperature Young's moduli and compressive strength of the specimens increased with decreasing porosity and were in the range of 1.6-14 GPa and 14-136 MPa, respectively. The mechanical properties of the 45%, 54% and 59% porous alloys were sufficient for both cortical and cancellous bone replacement applications. The alloy with a porosity content of 68% demonstrated mechanical properties suitable only for the cancellous bone implants. (C) 2021 Elsevier B.V. All rights reserved.