TY - JOUR

T1 - Rapid fabrication of function-structure-integrated NiTi alloys

T2 - Towards a combination of excellent superelasticity and favorable bioactivity

AU - Zhang, Lei

AU - He, Zhengyuan

AU - Tan, Jun

AU - Zhang, Yuqin

AU - Stoica, Mihai

AU - Prashanth, Konda Gokuldoss

AU - Cordill, Megan

AU - Jiang, Y. H.

AU - Zhou, Ru

AU - Eckert, Jürgen

PY - 2017/3/1

Y1 - 2017/3/1

N2 - Porous NiTi has brought new expectations to the field of orthopaedic implants due to its excellent mechanical properties such as high strength and superelasticity together with good biocompatibility. In order to facilitate the surrounding bone tissue ingrowth into the implanted porous alloy, reasonably large sized pores and a high amount of porosity are required. There is, however, a major challenge for clinical applications: the higher the porosity, the worse are the mechanical properties and the superelasticity. In this work, therefore, function-structure-integrated NiTi alloys consisting of a central solid and an outer porous layer were fabricated by spark plasma sintering (SPS). When sintered at 750 °C, the NiTi alloy with 14% porosity in the inner part and 49% porosity as well as 350 μm average pore size in the outer layer exhibits an exceptionally high compressive strength (∼1375 MPa), together with an excellent superelastic recovery strain (>4%) and favorable cellular affinity (ROS1728 osteoblasts). Altogether, this work provides a strategy to design materials with function-structure integration and suggests that properly designed function-structure integrated NiTi alloys may be promising as advanced bone implants.

AB - Porous NiTi has brought new expectations to the field of orthopaedic implants due to its excellent mechanical properties such as high strength and superelasticity together with good biocompatibility. In order to facilitate the surrounding bone tissue ingrowth into the implanted porous alloy, reasonably large sized pores and a high amount of porosity are required. There is, however, a major challenge for clinical applications: the higher the porosity, the worse are the mechanical properties and the superelasticity. In this work, therefore, function-structure-integrated NiTi alloys consisting of a central solid and an outer porous layer were fabricated by spark plasma sintering (SPS). When sintered at 750 °C, the NiTi alloy with 14% porosity in the inner part and 49% porosity as well as 350 μm average pore size in the outer layer exhibits an exceptionally high compressive strength (∼1375 MPa), together with an excellent superelastic recovery strain (>4%) and favorable cellular affinity (ROS1728 osteoblasts). Altogether, this work provides a strategy to design materials with function-structure integration and suggests that properly designed function-structure integrated NiTi alloys may be promising as advanced bone implants.

KW - Biomedical

KW - Interfaces

KW - Mechanical properties

KW - Porous materials

KW - Shape-memory effects (including superelasticity)

UR - http://www.scopus.com/inward/record.url?scp=84998892608&partnerID=8YFLogxK

U2 - 10.1016/j.intermet.2016.11.004

DO - 10.1016/j.intermet.2016.11.004

M3 - Article

AN - SCOPUS:84998892608

VL - 82.2017

SP - 1

EP - 13

JO - Intermetallics

JF - Intermetallics

SN - 0966-9795

IS - March

ER -