Effect of twin boundary on crack propagation behavior in magnesium binary alloys; Experimental and calculation studies

Somekawa, Hidetoshi*; Tsuru, Tomohito   

The impact of alloying elements on crack propagation and atomistic phenomenon at {102}-type twin boundaries in magnesium was investigated via both experiments and calculations. The alloying elements clearly affected crack propagation behavior. Cracks were difficult to propagate along matrix-deformation twinning interfaces in alloys that had high fracture toughness. In such magnesium alloys, the solute atoms, e.g., silver, manganese and zinc atoms, create adhesive interactions between magnesium atoms. Closed-shell and covalent-like bonding of these kinds of solute atoms would influence strong adhesion, which impedes the nucleation of a new surface at the twin boundary.