http://repository.iitr.ac.in/handle/123456789/24077| Title: | Modulated martensite formation behavior in Fe-Ni-based alloys; Athermal and thermally activated mechanisms |
| Authors: | Loewy S. Rheingans B. Meka, Sai Ramudu Mittemeijer E.J. |
| Published in: | Journal of Materials Research |
| Abstract: | The martensitic transformation of Fe-22 wt% Ni austenite was investigated by high-resolution dilatometry as well as differential thermal analysis. Macroscopically discontinuous formation of lath martensite was observed, manifested in a train of transformation-rate maxima. It is proposed that the modulation of the transformation rate is caused by simultaneous formation of blocks in different martensite packages. The origin of simultaneity is ascribed to the interplay of chemical driving force, developing strain energy, and its relaxation upon sufficiently slow cooling. The transformation-rate maxima become more distinct with decreasing cooling rate (CR), clearly indicating the involvement of a thermally activated process in martensite formation. Quantitative analysis of the microstructure of differently cooled specimens revealed smaller martensite block sizes for higher CRs. All observations are compatible with athermal nucleation and thermally activated growth. (Local) strain relaxation in the austenite was identified as the involved thermally activated mechanism. Copyright © Materials Research Society 2015. |
| Citation: | Journal of Materials Research, 30(13): 2101-2107 |
| URI: | https://doi.org/10.1557/jmr.2015.175 http://repository.iitr.ac.in/handle/123456789/24077 |
| Issue Date: | 2015 |
| Publisher: | Cambridge University Press |
| Keywords: | Austenite Differential thermal analysis Iron alloys Martensitic transformations Nickel alloys Strain energy Fe-Ni based alloys Lath martensite Martensite Formation Simultaneous formation Thermally activated Thermally activated mechanisms Thermally activated process Transformation rates Martensite |
| ISSN: | 8842914 |
| Author Scopus IDs: | 55965138600 36706528000 24503463800 35565640800 |
| Author Affiliations: | Loewy, S., Max Planck Institute for Intelligent Systems (Formerly Max Planck Institute for Metals Research), Stuttgart, D-70569, Germany, Institute for Materials Science, University of Stuttgart, Stuttgart, D-70569, Germany Rheingans, B., Institute for Materials Science, University of Stuttgart, Stuttgart, D-70569, Germany Meka, S.R., Max Planck Institute for Intelligent Systems (Formerly Max Planck Institute for Metals Research), Stuttgart, D-70569, Germany Mittemeijer, E.J., Institute for Materials Science, University of Stuttgart, Stuttgart, D-70569, Germany |
| Corresponding Author: | Loewy, S.; Max Planck Institute for Intelligent Systems (Formerly Max Planck Institute for Metals Research)Germany; email: s.loewy@is.mpg.de |
| Appears in Collections: | Journal Publications [MT] |
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