An atomistic study of resistance offered by twist grain boundaries to incoming edge dislocation in FCC metals

We explored 45 twist grain boundaries (GBs), spanning a broad range of misorientation angles (0°<θ<180°), to quantify the resistance offered to incoming lattice edge dislocation in different FCC metals (Al, Cu and Ni). The results provide corroborative evidence of the fact that GBs with higher energy offer strong resistance to incoming edge dislocation. Consequently, it has been found that: (1) the dislocation absorption resistance (stress at which dislocation is absorbed in the GB) follows a power-law relationship with the grain boundary energy, (2) grain boundary absorption resistance in FCC materials follow a simple statistical distribution, (3) the absorption resistance for the particular material is governed by the non-dimensional parameter γs/μbp, where γs is the stacking fault energy, μ is the shear modulus and bp is the Burgers vector of partial dislocations. It is envisioned that crystal plasticity based models could use this information to choose and define more realistic constitutive equations for grain boundaries.