Materials Research Letters (Dec 2024)

Optimizing strength-ductility synergy in lightweight steel via heterogeneous design: discontinuous fibrous ferrite

  • Qian Cheng,
  • Bo Yang,
  • Chao Zhang,
  • Xue Chen,
  • Wuli Su,
  • Xiaochong Lu,
  • Jianxiong Liang,
  • Wenquan Cao,
  • Chongxiang Huang

DOI
https://doi.org/10.1080/21663831.2024.2406913
Journal volume & issue
Vol. 12, no. 12
pp. 947 – 955

Abstract

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Disperse ferrite is generally embedded in lightweight steel, yet exhibits decent performance, thereby prompting a question: can heterogeneous design optimize it? Here, two representative structures, featured with discontinuous fibrous and dispersed ferrite separately embedded in the austenite matrix, were constructed as examples to address the issue. A heterostructure with fibrous ferrite shows a remarkable product (49 GPa·%) of ultimate strength and total elongation, standing out among other lightweight steels. Superior strength-ductility synergy is primarily attributed to hetero-deformation-induced strengthening and hardening. Abundant hetero-interactions imparted by phase boundaries, dense slip bands in austenite and dislocation networks inside ferrite serve as underlying physical mechanisms.

Keywords