Professor Mingxin Huang of the Department of Mechanical Engineering, together with his team and collaborators from partner institutions, conducted the research “Anisotropic lattice distortion makes ultrastrong martensitic steel ductile”. The research findings were published in Nature Materials on April 16, 2026.

Details of the publication:

Anisotropic lattice distortion makes ultrastrong martensitic steel ductile

S. Pan, B. B. He, M. X. Huang*

Article in Nature Materials

https://www.nature.com/articles/s41563-026-02588-5

Abstract

Making ultrahigh-strength as-quenched carbon martensitic steels ductile remains a critical challenge for structural applications. The ordered occupancy of carbon at interstitial sites in body-centred cubic martensite induces anisotropic lattice distortion, forming brittle body-centred tetragonal martensite with suppressed dislocation activity. Conventional tempering eliminates this distortion to improve ductility. Here we propose a counterintuitive strategy to unlock the ductility of a 2.4-GPa as-quenched carbon martensitic steel by utilizing the anisotropic lattice distortion of martensite. Its severe lattice distortion, that is, its high tetragonality, is driven by large-concentration substitutional solutes and carbon. The deliberately introduced high tetragonality activates deformation twins as a plastic carrier, effectively overcoming the brittleness of quenched carbon martensitic steel. This strategy of using solid-solution-induced anisotropic lattice distortion challenges the conventional view of tetragonal martensite’s inherent brittleness, establishing a framework for alloy design that yields strong and ductile metallic materials.