Abstract: The effect of extrusion temperature and speed on mechanical properties, surface quality and intergranular corrosion of extruded LY11 duralumin sections has been studied. The mechanical properties obtained under the conditions of higher extruding temperature and suitable flow speed were comparable to that of usual quenching process, while the surface quality desired was retained. The strengthening mechanism of this alloy quenched on extrusion press was also discussed. The strength decrease caused by the uncomplete solid solution in this process was compensated by the strength increase led by the appearance of vacancy sites and the substructure with high dislocation density.

Key words: Duralumin, Microstructure, Nature aging