Structure and thermomechanical behavior of NiTiPt shape memory alloy wires.

Published

Journal Article

The objective of this work is to understand the structure-property relationships in polycrystalline NiTiPt (Ti 42.7 at.% Ni 7.5 at %Pt) with a composition showing pseudoelasticity at ambient temperatures. Structural characterization of the alloy includes grain size determination and texture analysis while the thermomechanical properties are explored using tensile testing. Variation in heat treatment is used as a vehicle to modify microstructure. The results are compared to experiments on Ni-rich NiTi alloy wires (Ti-51.0 at.% Ni), which are in commercial use in various biomedical applications. With regards to microstructure, both alloys exhibit a <111> fiber texture along the wire drawing axis; however, the NiTiPt alloy grain size is smaller than that of the Ni-rich NiTi wires, while the latter materials contain second-phase precipitates. Given the nanometer-scale grain size in NiTiPt and the dispersed, nanometer-scale precipitate size in NiTi, the overall strength and ductility of the alloys are essentially identical when given appropriate heat treatments. Property differences include a much smaller stress hysteresis and smaller temperature dependence of the transformation stress for NiTiPt alloys compared to NiTi alloys. Potential benefits and implications for use in vascular stent applications are discussed.

Full Text

Duke Authors

Cited Authors

  • Lin, B; Gall, K; Maier, HJ; Waldron, R

Published Date

  • January 2009

Published In

Volume / Issue

  • 5 / 1

Start / End Page

  • 257 - 267

PubMed ID

  • 18718825

Pubmed Central ID

  • 18718825

Electronic International Standard Serial Number (EISSN)

  • 1878-7568

International Standard Serial Number (ISSN)

  • 1742-7061

Digital Object Identifier (DOI)

  • 10.1016/j.actbio.2008.07.015

Language

  • eng