Cracking of Alloy C-276 in an Acidic Environment

Austenitic Alloy C-276 has been identified as a structural material for application in hydrogen generation using nuclear heat. Fracture-mechanics-based pre-cracked and wedge-loaded double-cantilever-beam (DCB) specimens have been tested in an acidic solution at ambient temperature for 15 and 30 days. Three levels of initial stress intensity factors (K₁) were used to determine crack propagation following exposure of the DCB specimens to the test environment. The results indicate that the magnitude of K₁ was substantially reduced after testing, the extent of reduction being more pronounced with specimens tested for a longer duration. Three different types of failures namely, striations, cleavage and ductile, respectively were noted in the tested specimens, as determined by scanning electron microscopy.