FCC/HCP martensitic transformation and high-temperature shape memory properties in Co-Si alloys

Toshihiro Omori, Wataru Ito, Keisuke Ando, Katsunari Oikawa, Ryosuke Kainuma, Kiyohito Ishida

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


The microstructure, martensitic transformation temperatures and shape memory properties of Co-Si binary alloys were investigated by means of optical and transmission electron microscopy, differential scanning calorimetry and a shape memory test. The ε martensite phase with a hexagonal close-packed (hep) structure was observed to coexist with the face-centered cubic (fee) γ parent phase at room temperature. The γ/ε martensitic transformation temperatures linearly increased with Si content up to 4 mol%, but the trend flattened beyond 4 mol%Si while the transformation hysteresis and intervals monotonously increased. The Co-Si alloys exhibited shape recovery at high temperatures up to 900°C and a relatively high thermal stability up to 600°C. These results suggest that Co-Si alloy system has a possibility for high-temperature shape memory alloys.

Original languageEnglish
Pages (from-to)2377-2380
Number of pages4
JournalMaterials Transactions
Issue number9
Publication statusPublished - 2006 Sept


  • Cobalt-silicon
  • High-temperature shape memory alloy
  • Martensitic transformation
  • Shape memory effect
  • ε martensite

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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