Data for: Evolution of substructure in low-interstitial martensitic stainless steel during tempering

Published: 16 April 2020| Version 1 | DOI: 10.17632/b86py6xcs8.1
Contributors:
Frank Niessen,
Daniel Apel,
Frederic DANOIX,
John Hald,
Marcel Somers

Description

The evolution of the substructure and the distribution of interstitial elements in lath martensite during tempering in soft martensitic stainless steel X4CrNiMo16-5-1 was studied with line profile analysis of diffractograms from energy dispersive synchrotron X-ray diffraction, local chemical analysis with atom probe tomography and orientation mapping with electron backscatter and transmission Kikuchi diffraction. Martensite formation occurred below 135 °C without auto-tempering and led to a dislocation density in martensite of 3.8∙10^15 m^(-2), as determined from X-ray line profile analysis. On tempering carbon and nitrogen segregated to low-angle and high-angle grain boundaries. Recovery commenced above 550 °C and led to a reduction in dislocation density to a steady value of 4∙10^14 m^(-2) at 600 to 750 °C. Further tempering led to a second increase in dislocation density at room temperature, owing to the transformation of reverted austenite, formed above 650 °C, into martensite, on cooling. It was observed that the recovery of martensite competes with the formation of reverted austenite. The interpretation of the coherently diffracting domain size obtained from X-ray line profile analysis was critically discussed in the context of the internal structure in martensite.

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