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

ZT Li and SH Ma and SJ Zhao and WD Zhang and F Peng and Q Li and T Yang and CY Wu and DX Wei and YC Chou and PK Liaw and YF Gao and ZG Wu, MATERIALS TODAY, 63, 108-119 (2023).

DOI: 10.1016/j.mattod.2023.02.012

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 center dot lm1/2) and a pronounced solid solution strengthening (Drss = 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.

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