Porous fiber sintered β-type Ti-Zr-Nb-Sn biomedical alloys with superelasticity: Application towards cancellous bone implant with low porosity case

초록

Porous metal fiber sintered alloys are promising candidates for bone repair due to their readily tunable porosity with a wide range and fully interconnected open pore networks. In this work, the porous superelastic beta-type Ti-Zr-Nb-Sn alloys with porosities of 50%, 55%, and 60% were fabricated via metal fiber sintering for the application towards cancellous bone implant with low porosity case. The interior structure in porous specimens shows a three-dimensional network of bonded fibers. All solution-treated porous specimens consist exclusively of a single beta phase. An excellent combination of mechanical properties is achieved: a low elastic modulus (1.7-4.9 GPa) matching that of human cancellous bone with a low porosity case, a substantial recovery strain of 3.3-4.4%, and yield stresses ranging from 28 to 53 MPa. The stress-induced martensite transformation of beta -> alpha '' occurred during loading and was responsible for the superelastic recovery. The elastic modulus and yield stress are porosity-dependent and deviate from the theoretical values because of microstructural heterogeneities of the sintered fiber network. Importantly, the present Ti-Zr-Nb-Sn fiber sintering ensures an interstitial impurity-free beta-phase matrix in porous specimens. The present results underscore the potential of these porous Ti-Zr-Nb-Sn specimens for advanced applications in orthopaedic implants.

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