PREDICTING PLANE-STRAIN FRACTURE-TOUGHNESS OF AL-LI-CU-MG ALLOYS

The microstructural features that determine fracture toughness. and the mathematical models that relate those features to the plane strain fracture toughness, K(IC), for aluminum alloys are described. Particular attention is paid to the new class of Al-Li-Cu-Mg alloys. Models that relate fracture toughness to strain localization in the matrix and precipitation-free zones (PFZs) are evaluated based on experimental results of 8090 fracture behavior as a function of aging treatment. Good correlation was observed between experimental fracture toughness measurements and values predicted by the models. When verified, these models aid in identifying microstructural features that control fracture toughness and help in developing methods to improve this mechanical property.