Tensile properties, microstructures and fracture behaviors of an Al-Zn-Mg- Cu alloy during ageing after solution treating and cold-rolling

摘要

The tensile properties, microstructures and fracture behaviors of an Al-Zn-Mg-Cu alloy during ageing after solution treating and cold-rolling have been investigated. Tensile results show that high strength and acceptable ductility can be achieved simultaneously for the alloy. The enhanced strength, resulting from the combination of high-density dislocations, increased rolling textures, refined grains and nano-sized precipitates, changes with the precipitation characteristics and decreased dislocation densities. The improved ductility is attributed mainly to the decreased dislocation densities and meanwhile influenced by precipitation characteristics. The tensile fractographies are dominated by the dimple-induced transgranular fracture accompanied by small amount of intergranular fracture.