Description
In this study, a 3D microscopic dynamic phase field (PF) approach is developed to model dislocation processes in FCC single crystals. Being based on two order parameters per glide plane, this approach is formally similar to existing static Peierls–Nabarro (PN) approaches which are based on two disregistry fields per glide plane. In the current study, the PN approach is generalized to the dynamic case and compare with the PF approach. In both approaches, the energy model is based in particular on the stacking fault energy (SFE) of the material obtained from first-principle or atomic calculations. Given periodic fields and systems, the coupled system of evolution equations and mechanical equilibrium are solved using spectral and in particular Fourier methods. Example simulations using both of these approaches are performed in a comparative fashion for FCC metals with “low” SF energy (Cu) and “high” SF energy (Al). A number of processes involving single and dislocation loop systems are investigated. Depending on loading and other conditions, “low” SFE materials like Cu often tend to exhibit deformation based on the formation of multiple stacking fault layers and twinning. On the other hand, in “high” SFE materials like Al, the deformation often tends to be governed largely by dislocation glide. Examples will be given.
Recommended Citation
Svendsen, B. (2014). Microscopic phase field and Peierls-Nabarro modeling of dislocation dissociation, glide, and twinning in FCC systems. In A. Bajaj, P. Zavattieri, M. Koslowski, & T. Siegmund (Eds.). Proceedings of the Society of Engineering Science 51st Annual Technical Meeting, October 1-3, 2014 , West Lafayette: Purdue University Libraries Scholarly Publishing Services, 2014. https://docs.lib.purdue.edu/ses2014/mss/cppt/11
Microscopic phase field and Peierls-Nabarro modeling of dislocation dissociation, glide, and twinning in FCC systems
In this study, a 3D microscopic dynamic phase field (PF) approach is developed to model dislocation processes in FCC single crystals. Being based on two order parameters per glide plane, this approach is formally similar to existing static Peierls–Nabarro (PN) approaches which are based on two disregistry fields per glide plane. In the current study, the PN approach is generalized to the dynamic case and compare with the PF approach. In both approaches, the energy model is based in particular on the stacking fault energy (SFE) of the material obtained from first-principle or atomic calculations. Given periodic fields and systems, the coupled system of evolution equations and mechanical equilibrium are solved using spectral and in particular Fourier methods. Example simulations using both of these approaches are performed in a comparative fashion for FCC metals with “low” SF energy (Cu) and “high” SF energy (Al). A number of processes involving single and dislocation loop systems are investigated. Depending on loading and other conditions, “low” SFE materials like Cu often tend to exhibit deformation based on the formation of multiple stacking fault layers and twinning. On the other hand, in “high” SFE materials like Al, the deformation often tends to be governed largely by dislocation glide. Examples will be given.