[SY-C8] The influence of precipitate size and shape on the strengthening and hardening rate as observed within metallic alloys.
The interaction between glissile dislocations and precipitates within a continuum is responsible for marked increases in material strength. Due to their desirable engineering features, dislocation-obstacle interactions have been the subject of theoretical study for many decades. Despite ongoing efforts, these studies have often been limited to crude approximations whose validity is difficult to assess. Towards enhancing our understanding of these complex interactions, we employ a three dimensional coupled dislocation dynamics and finite element method computational scheme to directly compute the strength (i.e. bypass stress) of a variety of dislocation-precipitate interactions. The coupled framework accounts for elastic mismatch between the host matrix and precipitates via the inclusion of elastic image stresses and stress concentrations computed through the finite elements. Our simulations span a range of elastic mismatch, linear obstacle densities, degrees of ellipticity and size. Through our simulations, we demonstrate the influence of these four parameters on both the dislocation-precipitate strength, and hardening rate. We devise a simple mechanical model which yields insight into the results of both our numerical simulations as well as others found within the literature.