Effect of directional solidification on texture and magnetic-field-induced strain in Ni-Mn-Ga foams with coarse grains

Peiqi Zheng, Nikole J. Kucza, Zilong Wang, Peter Müllner, David C. Dunand*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Ferromagnetic Ni-Mn-Ga shape memory alloys with large magnetic-field-induced strains are promising candidates for actuators. Here, we cast replicated Ni-Mn-Ga foams with 57 vol.% of 355-500 μm open pores, with and without directional solidification. The 10M martensitic phase was determined in all foam samples. Directionally solidified foam had a fiber texture, with <1 0 0> closely aligned with the solidification direction. In contrast, foams without directional solidification were more randomly textured. One directionally solidified foam showed a maximum magnetic-field-induced strain of 0.65%, which was twice the value displayed by other foams without directional solidification. This improvement is consistent with a reduction in incompatibility stresses between neighboring grains deforming by twinning, generated by a reduction in crystallographic misorientation in textured foam.

Original languageEnglish (US)
Pages (from-to)95-101
Number of pages7
JournalActa Materialia
Volume86
DOIs
StatePublished - Mar 2015

Keywords

  • Directional solidification
  • Magnetic-field-induced strain
  • Nickel-manganese-gallium
  • Shape memory alloy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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