Synchrotron analysis of toughness anomalies in nanostructured bainite
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Authors
Abstract
High-resolution synchrotron X-ray diffraction has been used to characterise the notch root regions of Charpy impact test specimens of a superbainitic steel, both before and after loading. The changes in the volume fraction of austenite induced by the application of a three-point-bending load were quantified. Analysis of diffraction peak shifts revealed the extent of residual tensile and compressive strains present due to both machining and an applied load. The results lend support to the hypothesis that the comparatively low energies absorbed during Charpy impact testing of superbainitic steels, < 7 J, are due to the formation of stress-induced martensite at the notch root, prior to crack initiation.
Description
Keywords
Bainitic steel, Synchrotron diffraction, Charpy impact test, Toughness
Journal Title
Acta Materialia
Conference Name
Journal ISSN
1359-6454
1873-2453
1873-2453
Volume Title
105
Publisher
Elsevier BV
Publisher DOI
Sponsorship
Engineering and Physical Sciences Research Council (EP/H500375/1)
Engineering and Physical Sciences Research Council (EP/M005607/1)
Engineering and Physical Sciences Research Council (EP/M005607/1)
The authors are grateful to Prakash Srirangam Venkata and Bernard Ennis for their valuable contribution to the synchrotron work; to Diamond Light Source (Oxford) for access to the synchrotron facilities (under experiment EE8564); to Tata Steel UK and the Engineering and Physical Sciences Research Council of the UK for financial support (under EP/H500375/1 and EP/I02249X/1).