Abstract:A meso-scaled model was developed for the fracture toughness and tensile ductility of Al-Cu-Mg alloy based on the fact that the volume fraction of microcracks caused by the constituents cracking satisfies Weibull distribution under externally applied stress. Model analysis indicates that the volume fraction of microcracks caused by the constituents cracking increases with the externally applied stress. Under the same externally applied stress, the volume fraction of the microcracks increases with that of the constituents. The model calculation indicates that the fracture toughness and tensile ductility of Al-Cu-Mg alloy decrease as the size and volume fraction of the constituents increase. Thus, both purification and enhanced solution treatment can improve the tensile ductility and fracture toughness of Al-Cu-Mg alloy by decreasing the volume fraction and size of the constituents.

Key words: Al-Cu-Mg alloy; tensile ductility; fracture toughness; Weibull distribution