EFFECT OF IMPURITIES AND Ce ADDITION ON INTRINSIC AND EXTRINSIC TOUGHENING LEVELS OF 8090 Al-Li ALLOY
杂质及Ce对8090Al—Li合金内,外韧化水平的影响

The variability of intrinsic and extrinsic toughening levels has been derived for 8090 Al-Li alloy. The tensile properties and plane stress fracture toughness have been deter-mined for alloy 8090 sheets with various contents of impurities and Ce addition. Impurities Fe, Si and Na, K show an evident behavior to decrease the intrinsic toughening level and the fracture toughness even though the impurities could produce the extrinsic toughening effi-ciency to a certain degree. The intrinsic toughening level could be enhanced but the extrinsic toughening level is reduced by adding minor Ce element into alloy 8090 containing higher concentration of impurities. The intrinsic and extrinsic toughening levels are increased and the fracture toughness improved when the alloy containing higher concentration of impurities is modified by a fixed Ce content.