Simulation of dislocation glide in precipitation hardened materials

Multiscale modeling of precipitation hardening: Application to the Fe–Cr alloys

“…The main idea of this transition method is to interpret the AS results as a function of the effective stress on the dislocation segment pinned by the precipitate. This approach has already been used in analytical approaches [5] and in DD simulations of precipitate hardening [27,30]. At zero K, the precipitate cannot keep a dislocation segment pinned when it is submitted to an effective stress s eff larger than a critical value, called the obstacle resistance s obs .…”

“…At zero K, the precipitate cannot keep a dislocation segment pinned when it is submitted to an effective stress s eff larger than a critical value, called the obstacle resistance s obs . For example, if the shearing process creates an antiphase surface, s obs is equal to c/b [27], where c is the antiphase surface energy and b the norm of the Burgers vector. s obs is naturally connected to the classical strength F obs by F obs ¼ Dbs obs , where D is the diameter of the precipitate, considered to be of spherical form in all AS and DD simulations.…”

“…These flaws can be overcome using the DD simulation technique, where precipitates of finite size of arbitrary distribution can be mapped into the simulation box and dislocation-dislocation interactions are fully accounted for. The first DD investigations of PH were reported by Flush et al [25] and Mohles et al [26] and extended later to different interaction mechanisms [27,28]. Although a thorough progress has been made in these studies, the interaction potential was not built using ASs.…”

Dislocation dynamics simulations of precipitation hardening in Ni-based superalloys with high γ′ volume fraction

“…Recently, Mohles et al [3,4,5] have performed numerous twodimensional dislocation dynamics (DD) simulations in which one or few dislocations glide in a plane intersected by many coherent precipitates, but at a low volume fraction. In addition, Rao et al [6,7] have carried out DD simulations on g/g 0 superalloys with up to 40 vol.% of coherent precipitates.…”

Effect of particle size distribution on strength of precipitation-hardened alloys

“…In their simulation they introduced the criterion to determine the instability of the dislocation configuration in terms of the spacing of any two face-to-face bowed-out dislocation segments. Mohles et al [14][15][16] simulated dislocation glide using the local stress equilibrium 18 of particles. They considered a constant volume fraction and varied the particle radii to obtain underaged (essentially shearable), over-aged (non-shearable), and peak-aged particles.…”