In-situ TEM investigation of dislocation loop evolution in HR3 steel during Fe+ ion irradiation

Abstract

The evolution and characteristics of dislocation loops, which are affected by the value of temperature play a crucial role in the mechanical properties of structural materials. This study explores the evolution processes of the dislocation loops with the increasing values of the temperature, and the effect of precipitate on the dislocation loop. In-situ TEM experimental observations are performed using HR3 steel, which is commonly used as a structural material in nuclear reactors, during 400 keV Fe+ irradiation at room temperature (RT), 300 °C, 400 °C and 500 °C. The evolution of the dislocation loop at different values of the temperature is characterized in detail. The average size and density of dislocation loops as a function of displacement per atom (dpa) and values of temperature were constructed and analyzed comparatively. Irradiated samples at higher temperatures have a larger average size and a lower density of dislocation loops. The pre-existing dislocation lines have a profound effect on the density and Burgers vector of dislocation loops. Our present results provide a fundamental insight into the evolution and characteristics of dislocation loops in HR3 steel in a gradually changing of temperature environment.