Dependence of fracture toughness on multiscale second phase particles in high strength Al alloys

An improved model is described to predict variations in fracture toughness of high strength aluminium alloys with volume fraction, size, and characteristics of the contained multiscale second phases, i.e. ellipse shaped constituents, sphere shaped dispersoids, and disc shaped precipitates, in an integrated manner. Results show that predictions are in broad agreement with values measured experimentally for an aged Al-Cu-Mg alloy. Furthermore, the model was employed to relate the anisotropic fracture toughness of alloy plate to its orientation. A diagram is presented to illustrate the relationship between yield strength and fracture toughness of the aged alloy.