Achieving superb strength in single-phase FCC alloys via maximizing volume misfit

Zhongtao Li, Shihua Ma, Shijun Zhao*, Weidong Zhang, Fei Peng, Qian Li, Tao Yang*, Chia-Yi Wu, Daixiu Wei*, Yi-Chia Chou, Peter K. Liaw, Yanfei Gao*, Zhenggang Wu*

*Corresponding author for this work

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

91 Citations (Scopus)

Abstract

Single-phase face-centered cubic (SP-FCC) alloys normally possess low strength. Conventionally strengthening strategies inevitably cause significant ductility sacrifice. Here, a single-phase Ni-based FCC alloy with a superb yield strength of ∼1.05GPa and a good ductility of 37% is designed through maximizing the volume misfits. The misfit of the purposely targeted Ni80Mo20 alloy is severer than all existing FCC alloys, bringing the alloy a highest-ever Hall-Petch coefficient (kHP = 1034 MPa·μm1/2) and a pronounced solid solution strengthening (Δσss = 224 MPa). Current work yields two surprising and novel findings for SP-FCC alloys. First, volume misfit is a good pertinent indicator of kHP. Second, the conventional impression about the sole contribution of edge dislocations to strengthening in SP-FCC alloys may no longer hold; instead, screw dislocations can also kick in once the nonsphericity of the solute-induced stress field reaches a critical value. Altogether, this work paves a new avenue of pursuing ultimate strengthening without significant ductility sacrifice for SP-FCC alloys relying on the volume-misfit-maximization strategy.

© 2023 Elsevier Ltd.
Original languageEnglish
Pages (from-to)108-119
Number of pages12
JournalMaterials Today
Volume63
Online published3 Mar 2023
DOIs
Publication statusPublished - Mar 2023

Funding

The present work was supported financially by the National Key R&D Program of China (No. 2022YFE0200900). SZ acknowledges the support from Research Grants Council of Hong Kong (No. 11200421). TY greatly acknowledges the financial supports from the National Natural Science Foundation of China (No. 52101151). We also appreciate Dr. J.H. Luan for the support on the 3D-APT test. PKL very much appreciates the supports from (1) the National Science Foundation (DMR-1611180 and 1809640) and (2) the US Army Research Office (W911NF-13–1-0438 and W911NF-19–2-0049).

Research Keywords

  • Single-phase face-centered cubic alloys
  • Volume misfit
  • Solid-solution strengthening
  • Grain-boundary strengthening
  • Mechanical properties

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