Highly porous spark plasma sintered Ni-Mn-Ga structures

Frans Nilsén*, Joonas Lehtonen, Yanling Ge, Ilkka Aaltio, Simo Pekka Hannula

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

13 Citations (Scopus)

Abstract

A new approach for the processing of porous crystalline Ni-Mn-Ga compacts by spark plasma sintering (SPS) from a mixture of gas atomized Ni-Mn-Ga and NaCl powders (25/75 vol%) is reported. The NaCl was removed to reveal a highly porous skeleton of Ni-Mn-Ga. Solid skeletons were heat-treated in vacuum to grow the grains to a size of 22–23 μm, from the 1.7 μm found in the powder. The sample with the highest porosity showed a magnetic-field-induced strain of 1.24%. The MFIS is attributed to magnetically induced twinning due to the reduction of grain boundary constraints and the formation of preferred orientation.

Original languageEnglish
Pages (from-to)148-151
Number of pages4
JournalScripta Materialia
Volume139
DOIs
Publication statusPublished - 1 Oct 2017
MoE publication typeA1 Journal article-refereed

Keywords

  • Ferromagnetic shape memory alloy
  • Magnetic-field-induced strain
  • Porous material
  • Spark plasma sintering

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