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

The microstructural features that determine fracture toughness. and th e mathematical models that relate those features to the plane strain f racture toughness, K(IC), for aluminum alloys are described. Particula r attention is paid to the new class of Al-Li-Cu-Mg alloys. Models tha t relate fracture toughness to strain localization in the matrix and p recipitation-free zones (PFZs) are evaluated based on experimental res ults of 8090 fracture behavior as a function of aging treatment. Good correlation was observed between experimental fracture toughness measu rements and values predicted by the models. When verified, these model s aid in identifying microstructural features that control fracture to ughness and help in developing methods to improve this mechanical prop erty.