Shear response of the Σ11, ⟨1 1 0⟩ {131} symmetric tilt grain boundary studied by molecular dynamics

The deformation behavior of Al and Cu bicrystals with the Sigma 11, < 1 1 0 > {1 3 1} symmetric tilt grain boundary (STGB) under pure shear has been studied by molecular dynamics with embedded-atom method interatomic potentials. The simulated results indicate that the plastic strain of the bicrystals can be accommodated by GB migration coupled shear deformation or GB sliding, depending on the shear direction. Detailed study reveals that both the GB coupling motion and the GB sliding can be rationalized by the GB disconnection mechanism. The calculated coupling factors agree well with the vertical bar(b) over right arrow vertical bar/h ratios of the responsible disconnections. Based on these results, a shear-direction-dependent deformation behavior of this GB is proposed by placing special emphasis on the dominant role of the GB disconnections with a Burger's vector of the (1/22) < 4 7 1 > type.