The mechanical properties of Σ3 boundaries in binary stoichiometric material were studied by performing tensile tests on miniature bicrystalline specimens. It was found that Σ3 boundaries did not fracture in air. They were intrinsically strong and exhibited no environmental embrittlement; regardless of the grain boundary plane. An upper angular deviation limit, Δθc = 15Σ-1 ~ 15Σ-2/3, was suggested for the Σ3 boundary, depending upon the fracture behaviour. The boundaries which lay within Δθc did not fracture, whereas a boundary with an angular deviation                larger than Δθc exhibited brittle fracture. Themacroscopic slip behaviour at the grain boundary was found to be related to the specimen geometry. When the common slip system in both halves of the bicrystal was the primary slip system, slip could transfer readily across the grain boundary, leading to uniform deformation. Otherwise, slip was impeded at the grain boundary.

Mechanical Behaviour of Σ3 Boundaries in Ni3Al. J.Q.Su, M.Demura, T.Hirano: Acta Materialia, 2003, 51[9], 2505-15