After sintering both samples were annealed at xA deg C

Similar high build-up and low build-up interfaces were achieved for the sample aged for 60 min. Two representative APT reconstructions are shown in Fig. 6a and c, where Fe (0.4 at.%) and Mo (5.7 at.%) iso-concentration surfaces are displayed. A high build-up of Mo is observed in region 1 in Fig. 6a and low (no) build-up of Mo in region 2 in Fig. 6c. Note that CHIR265 high build-up of Mo is also present at the tip in Fig. 6c. The solute distribution in region 1 and 2 are plotted in Fig. 6b and d obtained by placing analysis cylinders 1 and 2 (20 nm and 18 nm in diameter respectively) perpendicular to the two types of interfaces. After ageing for 240 min, only high build-up interfaces were observed in all atom probe datasets due to the further coarsening of α precipitates. An example is shown in Fig. 6e, with the corresponding 1D concentration profile (21 nm diameter) shown in Fig. 6f. The Mo and V build-up length extends over a longer distance (>25 nm, which was the length of the dataset), making it appear less pronounced compared to the samples aged for 2 min and 60 min. Another dataset from the specimen aged at 923 K for 240 min provides evidence that by this stage the α plates have grown considerably (see supplementary material).