The influence of combined gradient structure with residual stress on crack-growth behavior in medium carbon steel

•Experimentally, we show that slower crack-initiation and faster crack-growth rate in the gradient samples in contrast to their gradient-free coarse-grain counterparts.•Using finite-element simulations, we show that both gradient structures and residual stress reduce the plastic deformation size and hence slow down crack initiation.•Based on the definition of the cyclic ΔJ-integral for small scale yielding, we explain that the presence of the residual stress leads to much lower ΔJ in contrast to the case without residual stress.