Abstract
At elevated temperature (550°C) in CO2 environment, intergranular creep cracks have been observed in thermally and environmentally aged 316H austenitic stainless steel. The objective of this work is to enhance the understanding of the creep crack mechanism and the effects of environment on crack initiation and growth. Some microtests on Single Edge Notched Tensile specimen (SENT) have been performed to better describe the interaction between chemistry and mechanics at the microstructural scale. A creep crack monitoring procedure using Digital Image Correlation (DIC) have been developped and assessed using Finite Element Modelling (FEM) of cracked bi-crystal. Based on a projection on Linear Elastic Fracture Mechanics expressions, the crack parameters (crack tip position, orientation) can be determined and the growth can be measured. A validation on in-situ tensile tests on SENT 316H specimen is proposed.