抄録
Magnesium alloys with a long-period stacking ordered (LPSO) structure show excellent mechanical properties such as high strength, relatively large ductility at room temperature. These superior properties are attributed to formation of kink-bands in LPSO-phase during material processing and the kinks may be expressed by dislocation and disclination. In order to reproduce numerically kink-bands, we extended a dislocation-based crystal plasticity model for HCP crystals developed by the authors previously to a new material model suitable for LPSO-phase. In this study, considering some characteristics of LPSO-phase in which non-basal slip and twin systems are hardly activated, we consider only the activation of basal slip system. Using this model, we carry out a two-dimensional FE analysis for a Mg-based LPSO-phase under a plane strain condition. Through this numerical simulation, the generation of kink-bands is computationally reproduced and the formation process of the deformation kinks is investigated in the view of the distributions of GN dislocation and GN incompatibility expressing dislocation pairs including the disclination. From a perspective of this investigation, we assume that the generation and the accumulation of GN dislocations and GN incompatibilities play a major role in formation of kink-bands. Furthermore, we observe a large angle of crystal rotation in kink-band region and we discuss about the effect of kink-bands on material strengthening.
