Mechanical Properties of Highly Porous NiTi Alloys

  • Martin Bram
  • Manuel Köhl
  • Hans Peter Buchkremer
  • Detlev Stöver
Article

DOI: 10.1007/s11665-011-9854-y

Cite this article as:
Bram, M., Köhl, M., Buchkremer, H.P. et al. J. of Materi Eng and Perform (2011) 20: 522. doi:10.1007/s11665-011-9854-y
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Abstract

Highly porous NiTi alloys with pseudoelastic properties are attractive candidates for biomedical implants, energy absorbers, or damping elements. Recently, a new method was developed for net-shape manufacturing of such alloys combining metal injection molding with the application of suitable space-holder materials. A comprehensive study of mechanical properties was conducted on samples with a porosity of 51% and a pore size in the range of 300-500 μm. At low deformations <6%, fully pronounced pseudoelasticity was found. Even at higher strains, a shape recovery of maximum 6% took place, on which the onset of irreversible plastic deformation was superposed. Results of static compression tests were also used to calculate the energy-absorbing capacity. Fatigue of porous NiTi was investigated by cyclic loading up to 230,000 stress reversals. The failure mechanisms responsible for a reduction of shape recovery after an increased number of load cycles are discussed.

Keywords

fatigue mechanical properties metal injection molding porous NiTi powder metallurgy space-holder technique 

Copyright information

© ASM International 2011

Authors and Affiliations

  • Martin Bram
    • 1
  • Manuel Köhl
    • 1
  • Hans Peter Buchkremer
    • 1
  • Detlev Stöver
    • 1
  1. 1.Forschungszentrum JülichInstitute IEF-1JülichGermany

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