Heterogeneous structure-induced strength-ductility synergy by partial recrystallization during friction stir welding of a high-entropy alloy

Po Ting Lin, Hung Chi Liu, Po Ying Hsieh, Cheng Yu Wei, Che Wei Tsai, Yutaka S. Sato, Shih Che Chen, Hung Wei Yen, Nian Hu Lu, Chih Hsuan Chen

Research output: Contribution to journalArticlepeer-review

Abstract

To apply high-entropy alloys (HEAs) for extensive advanced structural uses, their welding properties should be well understood. In this study, Al0.3CoCrCu0.3FeNi HEA was butt welded by friction stir welding (FSW). The fine-grained partially recrystallized microstructure in the stir zone gave rise to a high tensile yield strength of 920 MPa with an elongation of 37%. By microstructural observation, the excellent mechanical properties of the stir zone material were attributed to the partially recrystallized heterogeneous structure, with which the synergetic strengthening improved the strength of the HEA with considerably less trade-off in its ductility. This unique phenomenon was unprecedented in any other friction-stir welded conventional alloys and was credited to the low stacking-fault energy and the high grain growth activation energy of the HEA. This work suggests that FSW can not only produce good HEA welds but serve as a special processing technique to enhance mechanical properties of HEAs.

Original languageEnglish
Article number109238
JournalMaterials and Design
Volume197
DOIs
Publication statusPublished - 2021 Jan 1

Keywords

  • Friction stir welding
  • Heterogeneous structure
  • High-entropy alloys
  • Mechanical properties
  • Recrystallization

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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