Experimental determination of boundary energies of Σ9 [1 1 0] asymmetric tilt boundaries in Cu

A silica particle observation (SPO) method was used in order to determine experimentally the boundary energies of Σ9 [1 1 0] asymmetric tilt boundaries with a misorientation angle of θ = 38.9° in Cu for various inclination angles between ϕ = 0° and 90°. The SPO method has no drawbacks which are inevitable in boundary grooving and tri-junction methods. The boundary energy takes the maximum value at ϕ = 0° but the minimum value at ϕ = 65°. The minimum value is 65% of the maximum value. The inclination angle dependence of the boundary energy was utilized to evaluate quantitatively the possibility of faceting and dissociation for the boundary. According to the evaluation, the faceting into the {1 1 2}{5 5 2} and {5 5 2}{1 1 2} boundaries is possible for the {7 7 8}{1 1 0}, {5 5 4}{17, 17, 4} and {2 2 1}{2 2 1} boundaries. Furthermore, the dissociation into the Σ3 {1 1 1}{1 1 1} and {1 1 2}{1 1 2} twin boundaries is feasible for the {1 1 1}{1 1 5}, {4 4 7}{0 0 1} and {7 7 8}{1 1 0} boundaries.