M. Köhl, M. Bram, H. P. Buchkremer, D. Stöver, Forschungszentrum Juelich, Juelich, Germany
Highly porous NiTi alloys are attractive candidates for biomedical implants as well as for energy absorbers or damping elements. Recently, a method was developed for net-shape manufacturing of such alloys by combining metal injection moulding with the application of suitable space holder particles. A comprehensive study of mechanical properties was conducted varying porosity in the range of 30 - 70 Vol.% as well as pore size and pore shape. Fully pronounced shape memory properties were found even if they were superposed by irreversible plastic deformations at higher strains. Furthermore, fatigue of porous NiTi was investigated by cyclic loading up to 200,000 stress reversals. Based on the results, the potential of highly porous NiTi for the abovementioned applications is discussed.
Summary: Highly porous NiTi alloys were produced by metal injection moulding of pre-alloyed NiTi powders in combination with suitable space holder materials. Mechanical properties of these alloys were investigated in detail.
