Research on Microstructure Evolution Laws of Ultrafine Grained Metastable Automobile Steel

Abstract:

The microstructure evolution laws of ultrafine grained metastable automobile steels was studied in this paper by laser confocal scanning microscope, EBSD, XRD and TEM. Results showed that, the matrix organizations of hot-rolled steel were lath martensite and deformation ferrite, and there were a little of retained austenite film and lath between the lath martensite. After heat treatment, the matrix organizations of steel were ultrafine ferrite and retained austenite. The retained austenite transformed into martensite and ε-martensitic in the deformation process, and the strength and plasticity of steel were improved. A lot of retained austenite were obtained in the annealing process. The TRIP effects by the large fraction of metastable austenite and the ultrafine grain size add to the test steel with high strength and high plasticity.

• Periodical: Applied Mechanics and Materials (Volumes 423-426)
• Pages: 281-285
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.423-426.281
• Online since: September 2013
• Authors: Ji Guang Li*, Hai Liang Huang, Shang Wu Zeng, Jia Li Cao, Tie Jun Wang
• Keywords: Metastable Austenite, Microstructure Evolution, TRIP Effect, Ultrafine Grain Size

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