Effect of solid solution addition on the dislocation emission in aluminum alloys

Solid solution strengthening plays a key role in the strength increasing of alloying metals, due to that a solid solution of alloying element causes lattice distortion to a certain extent. In the paper, the effect of solid solution magnesium additions on the edge dislocation emission from a blunted crack tip in aluminum alloys is investigated. The critical stress intensity factor for the dislocation emission considering different magnesium solute concentrations is analyzed under the mode I and mode II loading conditions. The results show that within a certain concentration range the magnesium solute concentration does affect dislocation emission, although the influence appears not very strong. The critical stress intensity factor for the dislocation emission decreases with the increment of solute concentration. This means that relatively increasing the solute concentration can promote the dislocation emission, cause effective blunting of cracks and thus improve the fracture toughness of materials.