PSI- Issue 9

Jesús Toribio / Procedia Structural Integrity 9 (2018) 317–322 Author name / Structural Integrity Procedia 00 (2018) 000–000

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An additional reason for the improvement of fatigue performance with cold drawing is the blocking of dislocational movement (a basis for plastic crack advance) produced by the cementite lamellae, they being oriented with a higher angle in the cold drawn material and thus increasing the blocking effect and retarding the crack growth rate, because the cementite lamellae act as barriers or obstacles for dislocation movements, thereby retarding plastic crack advance by fatigue in the steel.

6. Following the wake of Antonio Machado and Fray Luis de León

The fatigue crack path recalls the words of the Spanish poet Antonio Machado: “se hace camino al andar”, as there is no previous path, but the path is made as the crack grows (and such a path is influenced by the material anisotropy regarding fatigue resistance, different for each steel). To include the idea of the material science effect, i.e., the influence of the oriented and aligned lamellar pearlitic microstructure (generated during manufacture by cold drawing) on the fatigue performance and on the crack paths, one remembers the verses of Fray Luis de León, major Spanish poet and Professor at the University of Salamanca: “y entrambas a porfía mezclan una dulcísima armonía”, indicating that the fight (the mixture) between voices ( the counterpoint ) generates the sweetest harmony, in the same manner as the mixture between ferrite and cementite lamellae produces a very noble material (pearlite steel), that can be considered, thus, a Fray Luis de León (FLL) based material. As the fatigue crack path generates a wake in the material (with tortuous shape), a wave in the sea generates its corresponding wake. The present paper was written following the wake of Antonio Machado and Fray Luis de León.

Fig. 7. Statue of Fray Luis de León in Salamanca.

Fig. 8. Logos of the University of Salamanca : traditional one (left) and modern one (right) celebrating the 800 th anniversary this year 2018.