Pursuing ultrastrong and ductile medium entropy alloys via architecting nanoprecipitates-enhanced hierarchical heterostructure

S. K. Guo, Z. L. Ma*, G. H. Xia, X. Y. Li, Z. Q. Xu, W. Z. Li, X. Y. Jin, X. W. Cheng

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

Nanoprecipitate-strengthened medium/high entropy alloys (M/HEAs) with ultrahigh strengths and unusual physical properties represent promising candidates for structural applications. However, further strengthening these materials usually relies on increasing the volume fraction of nanoprecipitates and/or introducing harder intermetallics that inevitably sacrifice the ductility. Here, we report a strategy to break this trade-off in a Co-Cr-Ni-based MEA by architecting a hierarchical heterostructure that integrates high-volume fraction (up to ∼30%) D022-γ’’ nanoprecipitates, shearable and non-shearable intermetallic particles, with a low stacking fault energy (SFE) matrix with heterogeneous grain structure. This hierarchical heterostructure can arouse hybrid strengthening mechanisms and lead to cross-scale and dynamic strain partitioning during plastic deformation, contributing to a superior strain-hardening capability and an excellent combination of the yield / ultimate tensile strength of 1323 MPa / 1690 MPa and 29% tensile elongation. This study provides a promising paradigm to design ultrastrong and ductile metallic materials via controlling multiscale microstructural heterogeneities.

Original languageEnglish
Article number119492
JournalActa Materialia
Volume263
DOIs
Publication statusPublished - 15 Jan 2024

Keywords

  • Hetero-deformation-induced strengthening
  • Hierarchical microstructure
  • Mechanical properties
  • Medium-entropy alloy
  • Precipitation strengthening

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