A novel Nb–TiNb nanocomposite with single-phase BCC structure for bio-implant applications

In the present study, a body-centered-cubic (BCC) structured Nb/TiNb multilayer nanocomposite with high yield strength, which comprises a soft TiNb matrix and reinforced Nb nanowires, was designed and fabricated with the aim of elucidating the strengthening mechanism of Nb/TiNb multilayer nanocomposite by scanning electron microscope, transmission electron microscopy and in situ synchrotron X-ray diffraction. It is observed that the Nb/TiNb nanocomposite possesses a high yield strength of ~ 640 MPa, significantly exceeding that of the conventional single-phase β-type Ti alloys. Further experimental results indicate that as plastic deformation commenced in the TiNb matrix of Nb/TiNb nanocomposite, load transfer from the soft TiNb matrix into the reinforced Nb nanowires occurred, allowing for a high load-bearing stress contribution and a significant strength enhancement of Nb/TiNb nanocomposite. Meanwhile, the embedded Nb nanowires can effectively impede the propagation of dislocation in TiNb matrix, further strengthening the present nanocomposite. These findings elucidate the strengthening mechanism of Nb/TiNb nanocomposite through the above two combinations, providing a basis for the design and development of the high-strength composites with a single-phase BCC structure for biomedical applications.