Grain boundary engineering for control of fatigue crack propagation in austenitic stainless steel

The roles of grain boundary microstructure in fatigue crack propagation during cyclic deformation were investigated in order to evidence the utility of grain boundary engineering for control of fatigue crack propagation in SUS304 austenitic stainless steel. It was found that the polycrystalline specimen with a higher fraction of low-∑ boundaries shows a lower crack propagation rate than the specimen with a lower fraction of them. Grain boundary microstructures play important role in the deflection, path and the local propagation rate of fatigue crack. The introduction of a higher fraction of {111}/∑3 boundaries leads to a lower contribution of intergranular fracture to the total crack length and a lower local propagation rate of fatigue crack in SUS304 stainless steel.