Superb strengthening behavior in a precipitation strengthened Co-rich CoCrNiAlTi medium entropy alloy with acceptable ductility

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

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  • X.H. Du
  • Y.H. Gai
  • C.X. Shi
  • G.S. Duan
  • B.L. Wu


Original languageEnglish
Article number107582
Journal / PublicationIntermetallics
Online published29 Apr 2022
Publication statusPublished - Jul 2022


For metallic materials, it is challenged to enhance the strain hardening rate under uniaxial tension when high flow stress is achieved. Here, we present a strategy enabling to obtain superior strain hardening ability via fabricating an incompletely recrystallized structure in a precipitation-strengthened Co-rich CoCrNiAlTi medium-entropy alloy. It involves to introduce a low-temperature ageing process in the CoCrNiAlTi alloy experienced high-strain cold rolling process. Accompanied with the formation of the partially recrystallized microstructure, high-density band-like L12-type ordered phase has formed via discontinuous precipitation. During the plastic straining process, deformation twins have been triggered by the high-stress field owing to its metastable structure. As expected, the alloy demonstrates synergistically substantial strengthening and toughening effects, thus, a superb mechanical property combination with ultimate tensile stress of 2.20 GPa and ductility of over 5.0% has been achieved at ambient temperature.

Research Area(s)

  • Co-Cr-Ni base Medium-entropy alloy, Mechanical properties, Strengthening mechanism, Twinning behavior