Evading the strength–ductility trade-off dilemma in steel through gradient hierarchical nanotwins

The strength-ductility trade-off has been a long-standing dilemma in materials science. This has limited the potential of many structural materials, steels in particular. Here we report a way of enhancing the strength of twinning-induced plasticity steel at no ductility trade-off. After applying torsion to cylindrical twinning-induced plasticity steel samples to generate a gradient nanotwinned structure along the radial direction, we find that the yielding strength of the material can be doubled at no reduction in ductility. It is shown that this evasion of strength-ductility trade-off is due to the formation of a gradient hierarchical nanotwinned structure during pre-torsion and subsequent tensile…

• NS
  National Science Foundation

  Awards: 1161749, CMMI-1161749
• NN
  National Natural Science Foundation of China

  Awards: 11002124, 2012CB937500, 11021262, 11272327, 11202183
• CA
  Chinese Academy of Sciences

  Award: 2012CB937500
• TU
  Tsinghua University
• DO
  Division of Civil, Mechanical and Manufacturing Innovation

  Award: CMMI-1161749