CRACK CLOSURE MECHANISM MAPS

The influence of various mechanical. metallurgical and environmental f actors on fatigue crack growth behaviour has been broadly explained by crack closure concept. Here, the concept of crack closure mechanism m ap is proposed with a view to predict crack closure mechanisms operati ve under given loading conditions for any microstructure/alloy system. Domains of various closure mechanisms are mapped in K-max-Delta K spa ce using boundary equations derived here. Based on the experimental da ta generated, the closure maps for a Ni-Cr free austenitic steel and a n AISI-4330 steel are constructed.