OS0609-371 Characteristics of Early Stage Creep Crack Growth around Cold Spots

Abstract

Behavior of small crack propagation during creep was studied by means of a hollow specimen with a simulated cooling notch, on the basis of non-linear fracture mechanics approach. Through the work special attention is paid to understand (i) microstructural aspects on the propagation behavior of the small creep crack interacting with grain boundaries and dendritic boundaries, (ii) difference between small cracks and physically long cracks, (iii) role(s) of stress concentration and its relaxation with creep time, and (iv) role of thermal gradient.