PSI - Issue 39

Georg Schnalzger et al. / Procedia Structural Integrity 39 (2022) 313–326 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Fig. 10. Microstructural characteristics of pearlitic steel in the: (a) undeformed state ( γ = 0) and (b) pre-deformed state ( γ ~ 3.5).

To correlate the crack path and microstructural anisotropy in the pre-deformed R260 the FCG specimen was loaded in Mode-I until ultimate fracture and a metallographic sample was extracted, as illustrated in the sketch in Fig. 11 (a). Fig. 11 (b) depicts the microstructure near the fracture surface observed close to the notch. The microstructural analysis confirms that the crack grows along the deformed pearlitic microstructure leading to the Mode-II dominated propagation, as already Fig. 9 showed, however without a local microstructural proof.

Fig. 11. Metallographic investigation of crack path in pre-deformed R260 ( γ ~ 3.5). (a) Sketch of extraction of metallographic sample from FCG specimen and (b) deformed pearlitic microstructure and crack path.