A Modeling Approach to Evaluate Grain Interaction Induced by {111}<011> Planar Slips in Face-centered Cubic Polycrystalline Materials

摘要

An accommodation deformation model to relax incompatibility between soft (yielded) and hard (non yielded) grains was proposed. Dislocation arrays were installed in the soft grain to investigate the effect of secondary slips on accommodating the displacement incompatibility due to the grain interaction at the grain boundary. When a secondary slip in the soft grain is active on the same plane as the dislocation arrays, it can accommodate the displacement incompatibility in almost all orientations. However, a dislo cation reflection on the primary slip plane is difficult to adopt for accommodation deformation. When the secondary slip in the soft grain is restricted to a plane without the primary slip, accommodation deforma tion in the soft grain does not occur. To accommodate the displacement incompatibility at the grain boundary, slip systems in the adjacent grain are required in almost all orientations. Around the orientation at which the secondary plastic deformation is the hardest to achieve, three slip systems are operating in areas of accumulation with high displacement incompatibility. Thus, the three slip systems should operate on different octahedral slip planes. However, the displacement incompatibility is not fully accommodated, and a stress field remains near the normal to {111}. The combination of sufficient stress concentration to open the grain boundary and the assembly of dislocations on the three slip systems at the grain boundary may be the cause of intergranular cracking.