Ultrastrong steel via minimal lattice misfit and high-density nanoprecipitation

Suihe Jiang, Hui Wang, Yuan Wu, Xiongjun Liu, Honghong Chen, Mengji Yao, Baptiste Gault, Dirk Ponge, Dierk Raabe, Akihiko Hirata, Mingwei Chen, Yandong Wang, Zhaoping Lu

研究成果: Article

253 引用 (Scopus)

抜粋

Next-generation high-performance structural materials are required for lightweight design strategies and advanced energy applications. Maraging steels, combining a martensite matrix with nanoprecipitates, are a class of high-strength materials with the potential for matching these demands. Their outstanding strength originates from semi-coherent precipitates, which unavoidably exhibit a heterogeneous distribution that creates large coherency strains, which in turn may promote crack initiation under load. Here we report a counterintuitive strategy for the design of ultrastrong steel alloys by high-density nanoprecipitation with minimal lattice misfit. We found that these highly dispersed, fully coherent precipitates (that is, the crystal lattice of the precipitates is almost the same as that of the surrounding matrix), showing very low lattice misfit with the matrix and high anti-phase boundary energy, strengthen alloys without sacrificing ductility. Such low lattice misfit (0.03 ± 0.04 per cent) decreases the nucleation barrier for precipitation, thus enabling and stabilizing nanoprecipitates with an extremely high number density (more than 10 24 per cubic metre) and small size (about 2.7 ± 0.2 nanometres). The minimized elastic misfit strain around the particles does not contribute much to the dislocation interaction, which is typically needed for strength increase. Instead, our strengthening mechanism exploits the chemical ordering effect that creates backstresses (the forces opposing deformation) when precipitates are cut by dislocations. We create a class of steels, strengthened by Ni(Al,Fe) precipitates, with a strength of up to 2.2 gigapascals and good ductility (about 8.2 per cent). The chemical composition of the precipitates enables a substantial reduction in cost compared to conventional maraging steels owing to the replacement of the essential but high-cost alloying elements cobalt and titanium with inexpensive and lightweight aluminium. Strengthening of this class of steel alloy is based on minimal lattice misfit to achieve maximal precipitate dispersion and high cutting stress (the stress required for dislocations to cut through coherent precipitates and thus produce plastic deformation), and we envisage that this lattice misfit design concept may be applied to many other metallic alloys.

元の言語English
ページ(範囲)460-464
ページ数5
ジャーナルNature
544
発行部数7651
DOI
出版物ステータスPublished - 2017 4 27
外部発表Yes

    フィンガープリント

ASJC Scopus subject areas

  • General

これを引用

Jiang, S., Wang, H., Wu, Y., Liu, X., Chen, H., Yao, M., Gault, B., Ponge, D., Raabe, D., Hirata, A., Chen, M., Wang, Y., & Lu, Z. (2017). Ultrastrong steel via minimal lattice misfit and high-density nanoprecipitation. Nature, 544(7651), 460-464. https://doi.org/10.1038/nature22032