Fabrication of NiTi Shape Memory Alloys with Graded Porosity to Imitate Human Long-bone Structure

Replacement of damaged long bones is still a significant challenge in surgery. In the present study, a NiTi Shape Memory Alloy (SMA) constructed with graded porosity imitating human long bone structure was fabricated via a dedicated moulding procedure. The outer layer (porosity 14 %) and inner layer (porosity 52 %) of the bone-like graded NiTi alloy were found to be co-axial very well with the interface with a good metallurgical bonding. Moreover, the compression strength and elastic modulus of the graded-porosity NiTi SMAs were found to be 360.6 MPa and 6.7 GPa, respectively, which have been improved by its coaxiality compared with the one with poor coaxiality. The graded-porosity NiTi SMAs exhibit resembling mechanical performance as human long-bones, and are considered to be better implant candidates for long bone replacement.