Notion of ductility transition temperature
Fracture tests - shock tests

We consider the case of metals that can fracture by cleavage: face-centered cubics and hexagonal metals, to the exclusion of face-centered cubics. The example most often considered is that of ferritic steels.

The yield strength R_e decreases with increasing temperature T (figure 5). At a critical temperature T_c, R_e meets the curve representative of the cleavage stress σ_f. Slightly above this temperature, during the tensile test, the specimen begins to deform plastically, collapses and ruptures by cleavage when the applied stress reaches σ_f. The elongation at break, a function...