Heat Treatment of Metals ›› 2024, Vol. 49 ›› Issue (7): 54-62.DOI: 10.13251/j.issn.0254-6051.2024.07.009

• MICROSTRUCTURE AND PROPERTIES • Previous Articles     Next Articles

Microstructure and mechanical properties of ultrafine grained heterostructured dual-phase steel prepared by warm rolling and intercritical annealing

Yan Wenchao, Gao Bo, Xiao Lirong, Zhou Hao   

  1. Nano and Heterogeneous Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing Jiangsu 210094, China
  • Received:2024-01-22 Revised:2024-04-25 Online:2024-07-25 Published:2024-08-29

Abstract: Comprehensive mechanical properties of the low-carbon steel were greatly improved by producing the ultra-fine grained heterostructured dual-phase (UFG-HSDP) structure. First, the initial structure of the low carbon dual-phase structure is refined by warm rolling at 300 ℃, and then the ultra-fine grained heterostructured dual-phase steel with high martensite content (volume fraction of77%) is obtained by intercritical annealing at 740 ℃. The average grain size of ferrite and martensite is 0.78 and 0.39 μm, respectively. The UFG-HSDP steel shows excellent comprehensive mechanical properties, with yield and tensile strengths of 1.26 and 1.75 GPa, respectively, while maintaining a uniform elongation of 6.2%. The mechanical incompatibility between ferrite and martensite in the UFG-HSDP steel during tensile deformation results in significant hetero-deformation induced hardening, which enhances the total strain hardening rate and thus improves the strength-ductility match of low-carbon steel.

Key words: low-carbon steel, heterostructured materials, mechanical properties, strain hardening, hetero-deformation induced stress

CLC Number: