Remarkable cryogenic properties by deformation twinning in a coherent precipitation-containing high entropy alloy

Y. L. Wang, K. C. Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)

Abstract

Developing structural alloys for critical cryogenic applications is a challenging yet essential task, primarily due to the ductile-brittle transition phenomenon. To address this issue, we developed a twinning-aided coherent precipitation-containing Co45Cr15Ni30Al5Ti5 high entropy alloy (HEA) with remarkable cryogenic properties. The activation threshold for twinning was successfully reduced via the disordering behavior of the L12 phase. In the present work, distinct temperature-dependent deformation behavior was observed. The dominant room-temperature strain accommodation mechanism was found to be the dislocation slip coupled with architectured stacking faults (SFs) and immobile Lomer-Cottrell (L-C) locks. Whereas, deformation twins were readily formed under cryogenic tensile loading, leading to significantly increased yield strength and ultimate tensile strength, approaching 1.5 GPa and 1.9 GPa, respectively. The remarkable cryogenic work hardening behavior contributes to persistent elongation of up to 31 % and the super-high ultimate tensile strength. The presence of SFs, deformation twins, and their interactions provide significant strain-hardening capability.

Original languageEnglish
Article number172572
Number of pages11
JournalJournal of Alloys and Compounds
Volume971
DOIs
Publication statusPublished - 15 Jan 2024

Keywords

  • Coherent precipitates
  • Cryogenic deformation
  • Deformation twins
  • High entropy alloys

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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