Effects of process parameters upon the shape memory and pseudo-elastic behaviors of laser-welded NiTi thin foil

C. W. Chan, H.C. Man, T. M. Yue

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)

Abstract

This article discusses the effects of laser welding parameters such as power, welding speed, and focus position on the weld bead profile, microstructure, pseudo-elasticity (PE), and shape memory effect (SME) of NiTi foil with thickness of 250 um using 100W CW fiber laser. The parameter settings to produce the NiTi welds for analysis in this article were chosen from a fractional factorial design to ensure the welds produced were free of any apparent defect. The welds obtained were mainly of cellular dendrites with grain sizes ranging from 2.5 to 4.8 um at the weld centerline. A small amount of Ni3Ti was found in the welds. The onset of transformation temperatures (As and Ms) of the NiTi welds shifted to the negative side as compared to the as-received NiTi alloy. Ultimate tensile stress of the NiTi welds was comparable to the as received NiTi alloy, but a little reduction in the pseudo-elastic property was noted. Full penetration welds with desirable weld bead profiles and mechanical properties were successfully obtained in this study.
Original languageEnglish
Pages (from-to)2264-2270
Number of pages7
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume42A
Issue number8
Early online date17 Feb 2011
DOIs
Publication statusPublished - Aug 2011

Keywords

  • Laser Welding
  • Taguchi Method
  • NiTi
  • Parameter Optimization

ASJC Scopus subject areas

  • Metals and Alloys

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