Comparison of Solute Nanoclusters in Fe-Cr-N Tempered Martensite Observed by Different Atom Probe Instruments

The solute clustering behaviors in Fe-1.0mass%Cr-0.3mass%N tempered martensite were comparatively studied by using three atom probe instruments, i.e. LEAP 4000 HR, 5000 XR, and 5000 XS. The microstructural features of nanoclusters were measured under the same conditions in voltage pulse mode, while statistical analysis including nearest neighbor distribution, radial distribution, frequency distribution, and cluster size distribution of Cr atoms were performed on the reconstructed datasets. The results revealed the superior capability of the LEAP 5000 XR to detect Cr nanoclusters in tempered martensite compared with the LEAP 4000 HR as a result of the improvement in detection efficiency and hit detection performance, whereas the high level of background in the mass-to-charge spectrum measured by the LEAP 5000 XS in voltage pulse mode limits its application in the detection of solute nanoclusters.