A new hot-rolled lightweight steel with ultra-high strength and good ductility designed by dislocation character and transformation strain

The method of Si substituting for Al was proposed to design a novel hot-rolled lightweight steel with ultra-high ultimate tensile strength (2046 MPa) and good total elongation after fracture (7.4%). The good ductility mainly originates from high screw dislocation fraction and transformation strain of retained austenite due to Si addition. This work breaks the impression of Si making steel brittle and deteriorate for many years and opens up a new route for alloy design through adjusting dislocation character and transformation strain.

Automated summary

This study proposes a method of substituting Si for Al to design a lightweight steel with ultra-high ultimate tensile strength and good ductility. The addition of Si contributes to a high fraction of screw dislocations and transformation strain of retained austenite, which enhances the ductility of the steel. This work challenges the long-standing belief that Si makes steel brittle and deteriorate, and offers a new approach to alloy design by adjusting dislocation character and transformation strain.