Mechanical stability of individual austenite grains in TRIP steel studied by synchrotron X-ray diffraction during tensile loading

Romain Blondé, Enrique Jimenez-Melero (Collaborator), Lie Zhao (Collaborator), Jon Wright (Collaborator), Ekkes Brück (Collaborator), Sybrand van derZwaag (Collaborator), Niels van Dijk (Collaborator)

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The stability of individual metastable austenite grains in low-alloyed TRIP steels has been studied during tensile loading using high-energy X-ray diffraction. The carbon concentration, grain volume and grain orientation with respect to the loading direction was monitored for a large number of individual grains in the bulk microstructure. Most austenite grains transform into martensite in a single transformation step once a critical load is reached. The orientation-dependent stability of austenite grains was found to depend on their Schmid factor with respect to the loading direction. Under the applied tensile stress the average Schmid factor decreased from an initial value of 0.44 to 0.41 at 243 MPa. The present study reveals the complex interplay of microstructural parameters on the mechanical stability of individual austenite grains, where the largest grains with the lowest carbon content tend to transform first. Under the applied tensile stress the average carbon concentration of the austenite grains increased from an initial value of 0.90 to 1.00 wt% C at 243 MPa, while the average grain volume of the austenite grains decreased from an initial value of 19 to 15 µm3 at 243 MPa.
    Original languageEnglish
    Pages (from-to)280-287
    Number of pages7
    JournalMaterials Science and Engineering A: Structural Materials: Properties, Microstructures and Processing
    Volume618
    DOIs
    Publication statusPublished - 2014

    Keywords

    • Steel
    • Martensite
    • Synchrotron X-ray diffraction
    • Tesnile deformation

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