Abstract
The microstructural evolution of a low carbon Fe–13%Cr–4%Ni–Mo (wt.%) martensitic stainless steel has been studied using transmission electron microscopy (TEM) and three-dimensional atom probe (3DAP). The as-quenched sample has a typical lath martensite structure, but carbon atoms were found to form ultra-fine clusters, or carbon-enriched regions, in the martensite. After a single-stage tempering at 680 °C, the steel mainly consists of the martensite and a certain amount of fine M 23C 6 carbides, which act as heterogeneous nucleation sites of the reversed austenite formed in the two-stage tempered (680 °C × 4 h + 600 °C × 4 h) samples. 3DAP investigations have revealed that the Ni, Cr and Mn atoms are enriched in the reversed austenite as contrasted with the martensite. Phosphorus atoms were uniformly distributed only in martensite, carbon was not detected in either martensite or austenite, and there was no segregation at the martensite–austenite interfaces. Those partitioning behaviors of the alloying elements were thought to be a factor contributing to the stability of the reversed austenite. High impact toughness at low temperature was obtained due to the existence of the reversed austenite.
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.