A novel method to define the effective average grain size of the materials with lath-typed microstructure: An example of medium manganese steel

Based on the mechanism of dislocation pile-up, a novel and concise method is proposed to define the effective average grain size of the medium Mn steel with the lath-typed microstructure. In order to investigate the HallPetch relationship of the medium Mn steel with different microstructural morphologies, the granular and lathtyped microstructures are fabricated by intercritical annealing (IA) and austenite reversed transformation (ART), respectively. The yield strength of the ART sample (lath-typed microstructure) exhibits excellent consistency with the Hall-Petch relationship obtained from the IA sample (granular microstructure) when adopting the effective average grain size, indicating the feasibility of the proposed method. In addition, the effect of grain size on the mechanical properties is also investigated.

Automated summary

A novel and concise method is proposed to define the effective average grain size of medium Mn steel with lath-typed microstructure, based on the mechanism of dislocation pile-up. The yield strength of lath-typed microstructure shows excellent consistency with the Hall-Petch relationship of granular microstructure, indicating the feasibility of the proposed method. Additionally, the effect of grain size on the mechanical properties is also investigated.