On the role of microstructure in governing the fatigue behaviour of nanostructured bainitic steels

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

卷:630

Article

Rementeria, Rosalia¹  Morales-Rivas, Lucia¹  Kuntz, Matthias²  Garcia-Mateo, Carlos¹  Kerscher, Eberhard³  Sourmail, Thomas⁴  Caballero, Francisca G.¹ 

[1] Spanish Natl Ctr Met Res CENIM CSIC, Dept Met Phys, E-28040 Madrid, Spain

[2] Robert Bosch GmbH, Mat & Proc Dept, D-70465 Stuttgart, Germany

[3] Univ Kaiserslautern, Mat Testing, D-67663 Kaiserslautern, Germany

[4] Ascometal CREAS Res Ctr Met, F-57301 Hagondange, France

关键词: Bainite;    Fatigue;    EBSD;    Steel;   

DOI  :  10.1016/j.msea.2015.02.016

来源: Elsevier

【 摘 要 】

Nanostructured bainite is not a novel laboratory-scale steel anymore and the interest on the commercial production of these microstructures by steelmakers and end-users is now conceivable. These microstructures are achieved through the isothermal transformation of high-carbon high-silicon steels at low temperature, leading to nanoscale plates of ferrite with thickness of 20-40 nm and retained austenite. Nanostructured bainitic steels present the highest strength/toughness combinations ever recorded in bainitic steels (2.2 GPa/40 MPa M-1/2) and the potential for engineering components is alluring. However, fatigue properties, responsible of the durability of a component, remain to be examined. In order to understand the role of the microstructure during the fatigue crack propagation, the crack path in three nanoscale bainitic structures has been analysed on the basis of the relationships between grain misorientations and grain boundaries by Electron Backscatter Diffraction. Active slip systems in bainitic ferrite and crack deflection at grain boundaries have been identified, while retained austenite is cast doubt on its role. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

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