Fatigue crack initiation from microstructurally small Vickers indentationsVuherer, Tomaž (Avtor) Godina, Andrej (Avtor) Burzić, Zijah (Avtor) Gliha, Vladimir (Avtor) welded jointsmicro defectcoarse grain HAZcrack initiationcrack growthstress concentrationfatigue limitVickersresidual stressesThe resistivity of coarse grain steel against crack initiation in the presence of micro defects is discussed. Samples of material with martensitic microstructure were prepared by adequate thermal treatment. Microstructurally small Vickers indentations were used as an artificial micro defect. The compressive residual stresses are due to the irreversibility of plastic deformation. The moment of indenting enables to prepare samples with and without effects of residual stresses. The stress level for crack initiation depends on the actual indentation size. The location of initiated cracks is affected by the presence and character of residual stresses.20072017-07-03 13:17:50Znanstveno delo66572sl