An Effect of Specimen Size on Fatigue Crack Growth and Plastic Zone Size

THE SIZE OF PLASTIC ZONES AND FATIGUE CRACK GROWTH BEHAVIOUR OF THREE FORMS OF A Ti–6Al–2.5Mo–1.5Cr ALLOY

“…The values of the constant d=0.12 (series A, B) and 0.245 (series F), as well as the data measured for the 'width of the plastic zone' versus DK ( Fig. 7) are in agreement with experimental results of other authors [9,[11][12][13], and with the data determined in steels in the previous study [10]. A comparison of Figs 5 and 6 indicates that the shift in the relationship between PZ and DK, measured in individual microstructures, is identical in essence with the shift in the FCG rate curves.…”

“…5 were minimized and the data converged to one central band. A similar case was described in Refs [12,13] which also showed the possibility of correlation of the size of PZ with FCG rate. On the other hand, the results showed that the electro-spark removal of the fracture surface behind the crack tip at the same value of DK and the size of PZ resulted in a decrease in the resistance to crack growth.…”

“…The size of PZ was measured on the surface of specimens by means of interference contrast G. R under a light microscope, similarly to Refs [9,10]. The dimension perpendicular to the crack growth direction was measured by common methods [9][10][11][12][13]. The specimens that were tested for resistance to FCG, and were fractured in the dynamic fracture toughness tests, were also examined by scanning electron microscope.…”