In situ synchrotron study on the interplay between martensite formation, texture evolution and load partitioning in low-alloyed TRIP steels

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

卷:528

Article

Jimenez-Melero, E.¹  Zhao, L.^2,3  Sietsma, J.³  Wright, J. P.⁴  van der Zwaag, S.⁵ 

[1] Delft Univ Technol, Fac Sci Appl, Dept Radiat Radionuclides & Reactors, NL-2629 JB Delft, Netherlands

[2] M2i, NL-2628 CD Delft, Netherlands

[3] Delft Univ Technol, Dept Mat Sci & Engn, NL-2628 CD Delft, Netherlands

[4] European Synchrotron Radiat Facil, F-38043 Grenoble, France

[5] Delft Univ Technol, Fac Aerosp Engn, NL-2629 HS Delft, Netherlands

关键词: Martensitic transformations;    TRIP steel;    Metastable austenite;    Synchrotron X-ray diffraction;    Mechanical characterization;   

DOI  :  10.1016/j.msea.2011.04.087

来源: Elsevier

【 摘 要 】

We have studied the micromechanical behaviour of two low-alloyed multiphase TRIP steels with different aluminium contents by performing in situ high-energy X-ray diffraction experiments at a synchrotron source under increasing tensile stress levels. A detailed analysis of the two-dimensional diffraction data has allowed us to unravel the interplay between the martensite formation, the texture evolution and the load partitioning, and to correlate the observed behaviour to the macroscopic response of the material. The high aluminium content TRIP steel grade presents a higher volume fraction of retained austenite at room temperature that transforms more gradually into martensite under deformation, providing a larger uniform elongation. The comparison between the observed transformation behaviour and the texture evolution indicates that the < 1 0 0 > component along the loading direction corresponds to a low critical stress for the transformation. The evolution of the elastic strains revealed the occurrence of a significant load partitioning before reaching the macroscopic yield strength, which becomes more pronounced in the plastic regime due to the progressive yielding of the different grains in the polycrystalline material. This opens the door to tailor the austenite stability by altering the distribution in grain size, local carbon content, and grain orientation in order to produce the optimal load partitioning and work hardening for improved combinations of strength and formability in low-alloyed TRIP steels. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

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