In-situ TEM study of dislocation emission associated with austenite growth

The emission of dislocations from the tip of a newly transformed austenite lath, with a near Pitsch orientation relationship with the ferrite matrix, was observed at 760 °C in a duplex stainless steel, using in-situ transmission electron microscopy. The dynamics of dislocation loops with [111]_b/2 Burgers vector were carefully analyzed. An estimation of stress concentration at the tip was made using dislocations as stress probes. These real-time observations verify directly for the first time that dislocation activity assists the growth of austenite precipitates, and provide quantitative data for revealing the stress field generated by interface migration.