Figure 2

Principle component score images of the ToF-SIMS data sets acquired after 34 days of charging.

(a) PC1 scores image for identifying phases using the positive ToF-SIMS data set acquired after 34 days of charging DSS with deuterium by using a peak list with secondary ions covering the main alloying elements. The bright regions represent the austenite phase (as proved by the loadings plot in shown Figure S2a). (b) PC1 scores image identifying locations rich in deuterium obtained from the negative SIMS data set acquired after 34 days and using the full peak list. Bright pixel indicate positive scores and correlate with the ferrite phase. (c) PC1 scores image obtained from the same data set but using a different peak list prepared to focus on carbides and nitrides. This image is identifying locations rich in N and C. Bright pixels indicate positive scores and correlate with the austenite phase. (d) PC2 scores image identifying locations rich in N, C and D (bright pixel means positive score) indicating graded accumulation of deuterium at the ferrite and austenite grain boundaries and at the ferrite/austenite interface (highest scores!) as well. All ToF-SIMS image acquisition settings and parameters are given in table S3 in SI.