fulltext.study @t Gmail

Structure and thermomechanical behavior of NiTiPt shape memory alloy wires

Paper ID Volume ID Publish Year Pages File Format Full-Text
2365 109 2009 11 PDF Available
Title
Structure and thermomechanical behavior of NiTiPt shape memory alloy wires
Abstract

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 <1 1 1> 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.

Keywords
Shape memory alloys; Thermomechanical properties; Nitinol; Platinum; TEM
First Page Preview
Structure and thermomechanical behavior of NiTiPt shape memory alloy wires
Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 5, Issue 1, January 2009, Pages 257–267
Authors
, , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering