Stress-ageing effects on the functional properties of high-strength [001]-oriented Ni51.0Ti37.3Hf12.5 single crystals

Elena Panchenko, Nikita Surikov, Yuriy Chumlyakov, Anna Eftifeeva, Aleksei Neiman, Huseyin Sehitoglu

Research output: Contribution to journalArticle

Abstract

The effects of stress-free and stress-assisted ageing at 873 K for 3 h on the crystal microstructure, the B2-B19' martensitic transformation (MT), the critical stress level for the stress-induced martensite formation, and the superelasticity (SE) in Ni-rich Ni51.0Ti37.3Hf12.5 (at.%) single crystals, oriented along the [001]B2 direction, were investigated. For the first time, it is experimentally demonstrated that ageing, under a compressive stress of 150 MPa along the [001]B2 direction, leads to the oriented growth of H-phase particles. The temperature range of SE and the critical stress level for martensite formation are determined by variation in the size (40-150 nm) and the number of crystallographic variants of the H-phase particles. Reversible stress-induced B2-B19' MTs at high levels of applied compressive stress up to 1750-1970 MPa, with the reversible strain of 1.1%, are observed in all investigated Ni51.0Ti37.3Hf12.5 single crystals.

Original languageEnglish (US)
Pages (from-to)4778-4783
Number of pages6
JournalMaterials Today: Proceedings
Volume4
Issue number3
DOIs
StatePublished - Jan 1 2017

Keywords

  • High-strength single crystals
  • Martensitic transformations
  • Ni-rich TiNiHf alloys
  • Superelasticity

ASJC Scopus subject areas

  • Materials Science(all)

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