Crack closure mechanism maps

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