Constructing multi-scale retained austenite makes bainitic steel better mechanical properties by introducing weak chemical heterogeneity

Abstract

Overcoming the trade-off relationship between strength and ductility has always been a challenge. In this article, a neatly arranged ultrafine bainite that is composed of multi-scale retained austenite was obtained by introducing weak chemical heterogeneity in low-alloy steel. The optimized microstructure makes transformation-induced plasticity (TRIP) behavior and coordinating deformation behavior between each phase to be smoother. This results in better comprehensive properties, with 28.5% and 9% increases in uniform elongation and toughness, respectively, and a similar strength. This study provides a new way to improve the properties of low-alloy steels.

GRAPHICAL ABSTRACT

IMPACT STATEMENT

A strategy of weak chemical heterogeneity has been proposed in low-alloy steel, which effectively optimizes the microstructure and enhances the plasticity and toughness of steel.

KEYWORDS:

• Rapid heating
• chemical heterogeneity
• retained austenite
• ultrafine bainite
• plasticity and toughness

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors would like to thank the funding support to this work from the National Key R & D Program Young Scientists Project (grant number 2021YFB3703500), the National Natural Science Foundation of China (grant number 52122410, 52374406), the Natural Science Foundation of Hebei Province (E2023203259), for funding this research.