Niu, G., Jin, D., Gong, N., & Misra, R. D. K. (2023). Achieving excellent strength and ductility synergy by δ phase strengthening in low-density high-manganese steel. Materials Technology, 38(1). https://doi.org/10.1080/10667857.2023.2283991
Abstract:
In this study, we developed a novel lightweight Fe-Mn-Al dual-phase with high strength, excellent ductility, and considerable toughness. The study involved a thorough exploration of heat treatment processes and mechanical behaviour. The microstructure of the Fe-Mn-Al dual-phase steel consists of austenite and δ-ferrite. In the early stages of plastic deformation, austenite undergoes primary deformation, leading to a faster increase in dislocation density and microhardness. In later stages, strain is transferred from austenite to δ-ferrite through high-density dislocation walls, resulting in coordinated deformation of the two-phase structure. The excellent strength-ductility combination of Fe-Mn-Al dual-phase steel is attributed to multiple stages of continuous work hardening. Initially, dislocation nodes in δ-ferrite contribute to work hardening. Subsequently, high-density dislocation structures and the strengthening effect of hard δ-ferrite enhance work hardening. Finally, deformation twins in austenite, along with the TWIP effect, further increase work hardening, emphasizing the importance of these interactions in improving mechanical performance.
License type:
Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Funding Info:
This research / project is supported by the Agency for Science, Technology and Research - Structural Metal Alloys Programme
Grant Reference no. : A18B1b0061
This research / project is supported by the Agency for Science, Technology and Research - Manufacturing of Multi-Material Net-Shape Parts with Heterogeneous Properties (MMNH)
Grant Reference no. : M22K5a0045