Prediction impact behavior of functionally graded steel by strain gradient plasticity theory

Functionally graded ferritic and austenitic steels were produced through electroslag refining by setting the austenitic and plain carbon steels with appropriate thickness as electrode. Charpy impact energy of the specimens has been studied and modeled regarding the mechanism-based strain gradient plasticity theory. The yield stress of each layer was related to the density of the statistically stored dislocations of that layer and assuming Holloman relation for the corresponding stress–strain curves, tensile strengths of the constituent layers were determined via numerical method. Charpy impact energy of each layer was related to the corresponding area under stress–strain curve of that layer and finally by applying the rule of mixtures, Charpy impact energy of functionally graded steels was determined. The obtained results from the proposed model are in good agreement with the experimental ones.