High-temperature in-situ TEM Straining of the Interaction with Dislocations and Particles for Cu-added Ferritic Stainless Steel

Cu is always present in the matrix when ferritic steels were prepared from ferrous scrap. When the ferritic steels are aged thermally, Cu precipitates start appearing and dispersing finely and homogeneously, which may result the steels strengthened by precipitation hardening. In this study, the interactions between Cu precipitates and dislocations were examined via high-temperature in-situ TEM straining. Cu-added ferritic stainless steel (Fe-18.4%Cr-1.5%Cu) was used in the present study. Specimen was aged at 1073 K for 360 ks. Microstructure of specimen was analyzed by JEM-3200FSK and high-temperature in-situ TEM straining was conducted using JEM-1300NEF. Progressing dislocations in matrix contacted with the Cu precipitate at right angle. This result implies that there is an attractive interaction between dislocations and the Cu precipitate. Furthermore, dislocations pass through the particle after contacting it, so that the interaction with dislocations and particles should be explained by Srolovitz mechanism.