Work hardening behaviour in banded dual phase steel structures with improved formability

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:713

Article

Ennis, B. L.^1,2  Bos, C.¹  Aarnts, M. P.¹  Lee, P. D.^2,3  Jimenez-Melero, E.² 

[1] Tata Steel Res & Dev, NL-1970 CA Ijmuiden, Netherlands

[2] Univ Manchester, Sch Mat, Oxford Rd, Manchester M13 9PL, Lancs, England

[3] RAL, Manchester Xray Imaging Facil, Res Complex Harwell, Didcot OX11 0FA, Oxon, England

关键词: Mechanical characterization;    Hardening;    Steel;    Austenite;    Martensite;    Thermo-mechanical processing;   

DOI  :  10.1016/j.msea.2017.12.078

来源: Elsevier

【 摘 要 】

In this work, we show how the presence of microstructural banding and segregation affects the work-hardening behaviour of a dual phase steel with improved formability. This steel contains chemical segregation inherited from the casting process. Our previously developed 3D cellular automaton model allowed us to design thermo-mechanical processes to either promote or suppress banding. The bands are properly described as in-plane sheets of martensite grains. Mechanical testing data revealed a significant reduction in tensile strength in banded structures for a similar level of ductility. The work-hardening behaviour in the pre-yield regime, including the yield strength itself, is not correlated to the incidence of segregation and/or microstructural banding. The reduction in ultimate tensile strength in banded structures stems from a reduced work-hardening capacity in the post-yield regime. This is due to increased austenite stability in the banded steels, coupled to the anisotropic strain localisation in the ferritic matrix between martensite bands.

【 授权许可】

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