Chemical complexity-changed deformation behavior of NiTi-based B2 low- to high-entropy intermetallic compounds: Atomistic simulations

Cheng Yuan Tsai, Chi Huan Tung, Chun Cheng Chen, Shou Yi Chang

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Owing to the high chemical complexity and severe lattice distortion but still long-range ordered structure, the deformation behavior and defect activities of high-entropy intermetallic compounds are worth investigations. Hence in this study, the mechanical properties of NiTi-based low- to high-entropy intermetallic compounds were measured from different orientations at different temperatures simply by using nanoindentations, and compared with the structural evolution and defect activities suggested by molecular dynamics simulations. The deformation of the low-entropy intermetallic compound proceeded with regular martensitic transformation, followed by the heterogeneous nucleation of dislocations at the martensite/austenite interface and the subsequent long-distance gliding accompanied with sharp stress drops. With increasing temperature, a more intense shearing events and marked strength reduction were observed. In comparison, with the introduction of constitutional complexity, the martensitic transition was suppressed. Instead, the early homogeneous nucleation at a relatively small activation volume (acquired from indenting displacement bursts) and small-range activities of abundant defects mediated the smooth stress-strain response and uniform plastic deformation of the high-entropy intermetallic compound. At an elevated temperature, a similar deformation mechanism and the same level of strength were retained in the chemically complex alloy.

Original languageEnglish
Article number171557
JournalJournal of Alloys and Compounds
Volume966
DOIs
StatePublished - Dec 5 2023
Externally publishedYes

Keywords

  • High-entropy alloy
  • Intermetallic Compound
  • Martensitic transformation
  • Molecular dynamics simulations
  • Plastic deformation

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