PSI - Issue 68

Shanyavskiy A. et al. / Procedia Structural Integrity 68 (2025) 453–457

456

4

A. Shanyavskiy et al. / Structural Integrity Procedia 00 (2025) 000–000

a

b

c

d

Fig. 3. (a, b) Region of facetted fracture surface reflecting material lamellar structure at (a) secondary and (b) back-scattered electron regimes of SEM operation; (c) subsurface crack origin (inside ellipse) ahead of a crack tip along with pronounced crack fronts directed to notch (left arrow) and bulk material (right arrow); (d) flat facets performed by the alpha-phase ahead of a crack tip (with arrows indicating crack growth direction). The results of simulations are shown in Fig. 4. The numerical simulation of crack front shape under high-frequency loading shows a suitable agreement with experimental results. Based on the obtained results the following conclusions can be stated. 4. Conclusion The crack propagation after its arrest in the specimens made of titanium alloy Ti-6Al-4Mo is associated with the new crack nucleation ahead of and from the main crack tip. The crack propagation in the VHCF region is performed in quasi-brittle manner with formation a relief reflecting the two-phase alpha-beta structure of the titanium alloy in the form of a globular or lamellar shape. A method for numerical modeling of the fatigue crack front shape in the VHCF region has been developed based on the finite element method program, which provides satisfactory convergence of the calculated and experimental crack front shape.