Physique et mécanique de l'endommagement

Ductile fracture of high strength steels with morphological anisotropy, Part I: Characterization, testing, and void nucleation law

“…12. In both cases, void nucleation occurs early in the loading process but the voids nucleate differently depending on the loading direction, a phenomenon known in the literature for a long time [6]. After image processing, the surface fraction of the MnS inclusions and of their associated surrounding cavity is computed.…”

“…The fracture strains estimated from the experimental tests following Eqs. (4,5,6), and used to extract Figs. 17a and 17b are based on the area reduction at the notched section after full fracture.…”

“…The experimental fracture strains defined by Eqs. (4,5,6) are all macroscopic quantities. Although these macroscopic values are approximations of the stress and strain states of the location and instant of cracking initiation in the minimum cross-section, they still provide reasonable trends in terms of the impact of the stress triaxiality and of the Lode parameter as shown in Figs.…”

“…Voids can nucleate by either particle fracture or particle decohesion. These two mechanisms have been widely investigated, see reviews [4,5,6,7,3]. Void nucleation can occur early in the deformation process during the elastic loading or after minute amounts of plasticity, or sometimes only at very large deformation.…”

Influence of Boundary Migration Induced Softening on the Steady State of Discontinuous Dynamic Recrystallization

“…In uniaxial compression, the latter is defined as the ratio between the axis parallel to the compression direction and a perpendicular axis, which is given by (Equation (18)): where ε denotes here the von Mises equivalent strain. In simple shear (corresponding to the classical torsion test), the relationship between λ and ε is more complex, but it is easy to show that it is numerically very close to Equation (18) (see for instance [ 23 ]).…”