Abstract
The austenite → martensite transformation occurring upon cooling of an FeNiCoMo alloy, similar to commercial FeNiCoMo maraging steels, thereby forming lath martensite, was investigated by dilatometry with regard to the influence of an externally applied compressive load on the peculiar transformation behavior in this system, which exhibits a step-wise mode of transformation upon slow cooling, as shown recently. Temporary, external loading during isothermal interruption of the continuous cooling at different stages of the transformation revealed a decreasing degree of plastic deformation proportional with the decreasing amount of retained austenite, implying that the plastic deformation is predominantly accomplished within the austenite phase. Upon resuming the cooling, the step-wise transformation was found to be unaffected. Application of a constant, comparatively high external load during continuous cooling caused a step-wise length decrease in the temperature range of the transformation instead of the step-wise length increase observed for the martensitic transformation in absence of an external load. The plastic deformation happening during the transformation occurs also for loads below the yield limit of pure austenite. This genuine transformation-induced plasticity was ascribed to the generation of mobile dislocations within the austenite upon the formation of martensite, thereby enabling plastic deformation in addition to the intrinsic deformation induced by the load for a specimen in the absence of transformation. Because the transformation into martensite also during loading takes place in a step-wise manner, the generation of these mobile dislocations occurs step-wise too, thus leading to the observed step-wise plastic deformation and corresponding step-wise length decrease during the transformation.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.