The ab initio tensile test was applied to an Al Σ9 grain boundary by using the ab initio pseudopotential method. The theoretical tensile strength was 9.50GPa at the strain 21%. As compared with the theoretical tensile strength in the direction [001] or [111] of an Al single crystal, the boundary was still strong due to the interface reconstruction. The interface extends at almost the same rate with the bulk interlayer until the strain of 19% in spite of the reduced number of interfacial bonds, which indicates the special strength of the reconstructed bonds. This feature could be regarded as a typical property of Al that strong local bonds were formed for less-coordinated atoms at defects.

Theoretical Tensile Strength of an Al Grain Boundary. G.H.Lu, S.Deng, T.Wang, M.Kohyama, R.Yamamoto: Physical Review B, 2004, 69[13], 134106 (9pp)