Three-dimensional vacancy diffusion analysis related to micro damage of C(T) specimen for P92 steel under creep condition

In this study, interrupted creep crack growth tests were conducted using C(T) specimens with side-grooves of P92 steel. After the interrupted tests, to investigate the creep crack growth behavior of P92 steel under the multi-axial stress field, the creep crack growth path of the center of the thickness direction and near the side-groove were observed. From observational results, it was indicated that the creep crack preferentially grew near the side-groove. Additionally, creep crack growth forms were different between the center of the thickness direction and near the side-groove. For the center of the thickness direction, the creep crack growth behavior showed the periodic convexo-concave manner. On the other hand, the creep crack grew in a linear manner near the side-groove. To mechanically clarify the difference of creep crack growth forms, three-dimensional diffusion analysis of vacancies which related to the void formation and crack growth was conducted. From analytical results, vacancies accumulated at the corner of the bottoms of notch and side-groove. This result is in good agreement with the experimental result.