In situ 3D crystallographic characterization of deformation-induced martensitic transformation in a metastable Fe-Cr-Ni austenitic alloy by X-ray microtomography.

Excellent strength-ductility balance in metastable Fe-Cr-Ni austenitic alloys stems from phase transformation from austenite (fcc structure) to α' martensite (bcc structure) during deformation, namely deformation-induced α' martensitic transformation (DIMT). Here, DIMT in a metastable Fe-17Cr-7Ni austenitic alloy was detected in situ and characterized in three dimensions (3D) by employing synchrotron radiation X-ray microtomography. This technique utilizes refraction contrast, which is attributable to the presence of phase boundaries between the parent austenite and the newly formed α' martensite phase.

High-energy x-ray nanotomography introducing an apodization Fresnel zone plate objective lens.

In this study, high-energy x-ray nanotomography (nano-computed tomography, nano-CT) based on full-field x-ray microscopy was developed. Fine two-dimensional and three-dimensional (3D) structures with linewidths of 75 nm-100 nm were successfully resolved in the x-ray energy range of 15 keV-37.7 keV.

Transmission electron microscopy/electron energy loss spectroscopy measurements and calculation of local magnetic moments at nickel grain boundaries.

We have determined local magnetic moments at nickel grain boundaries using a transmission electron microscopy/electron energy loss spectroscopy method assuming that the magnetic moment of Ni atoms is a linear function of the L/L (white-line ratio) in the energy loss spectrum. The average magnetic moment measured in the grain interior was 0.55 , which agrees well with the calculated magnetic moment of pure nickel (0.