Gradient cell–structured high-entropy alloy with exceptional strength and ductility

By Qingsong Pan, Liangxue Zhang, Rui Feng, Q. Lu, K. An, A. Chuang, J. Poplawsky, P. K. Liaw, Lei Lu. Science, 2021

674 citations recorded by the source corpus.

Description Strength by cyclic torsion For most alloys, conventional or high entropy, increasing strength comes at the cost of poor ductility. Although there are many strategies to break this inverse relationship, Pan et al. now show that cyclic torsion on a high-entropy alloy enhances strength without degrading ductility (see the Perspective by Yeh). Cyclic torsion creates a gradient of dislocations and low-angle grain boundaries from the surface to the interior that organize into tiny stacking faults and twin when straining begins. These structures allow for the good ductility while simultaneously helping to work harden the alloy. —BG Cyclic torsion of a high-entropy alloy creates a gradient dislocation structure that leads to high strength and ductility. Similar to conventional materials, most multicomponent high-entropy alloys (HEAs) lose ductility as they gain strength. In this study, we controllably introduced gradient nanoscaled dislocation cell structures in a stable single-phase HEA with face-centered cubic structure, thus resulting in enhanced strength without apparent loss of ductility. Upon application of strain, the sample-level structural gradient induces progressive formation of a high density of tiny stacking faults (SFs) and twins, nucleating from abundant low-angle dislocation cells. Furthermore, the SF-induced plasticity and the resultant refined structures, coupled with intensively accumulated dislocations, contribute to plasticity, increased strength, and work hardening. These findings offer a promising paradigm for tailoring properties with gradient dislocation cells at the nanoscale and advance our fundamental understanding of the intrinsic deformation behavior of HEAs.

Subfields: Aerospace Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/8810b778ea59e2f559dbe25635f9537f37d81860

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In Aerospace Engineering

  1. Xianglin Liu
  2. Zongrui Pei
  3. Jiaxin Zhang

In Mechanical Engineering

  1. Xianglin Liu
  2. Zongrui Pei
  3. Jiaxin Zhang

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