STRESS DISTRIBUTION NEAR GRAIN BOUNDARY IN ANISOTROPIC BICRYSTALS AND TRICRYSTALS

The rate dependent crystallographic finite element program was implemented in ABAQUS as a UMAT for the analysis of the stress distributions near grain boundary in anisotropic bicrystals and tricrystals, taking the different crystallographic orientations into consideration. The numerical results of bicrystals model with the different crystallographic orientations shows that there is a high stress gradient near the grain boundaries. The characteristics of stress structures are dependent on the crystallographic orientations of the two grains. The existing of triple junctions in the tricrystals may result in the stress concentrations,or may not, depending on the crystallographic orientations of the three grains. The conclusion shows that grain boundary with different crystallographic orientations can have different deformation, damage, and failure behaviors. So it is only on the detail study of the stress distribution can the metal fracture be understood deeply.