HIGH-STRENGTH ALUMINUM-BASE ALLOY PRODUCTS AND PROCESS FOR PRODUCTION THEREOF

摘要

A heat-treated high-strength Al-Cu-Mg-Si aluminum alloy product exhibits excellent extrudability and high strength. The high-strength Al-Cu-Mg-Si aluminum alloy product obtained by extrusion is characterized in that the microstructure of the entire surface of the cross section of the aluminum alloy product is formed of recrystallized grains, the grains have an average aspect ratio (L/t) of 5.0 or less (wherein L is the average size of the grains in the extrusion direction, and t is the average thickness of the grains), and the orientation density of the grains in the microstructure, for which the normal direction to the {001} plane is parallel to the extrusion direction in comparison with the grains orientated to random orientations, is 50 or less. The high-strength Al-Cu-Mg-Si aluminum alloy product obtained by extrusion and cold working is characterized in that rod-shaped precipitates are arranged in the grains of the matrix in the <100> direction, the precipitates have an average length of 10 to 70 nm and a maximum length of 120 nm or less, and the number density of the precipitates in the [001] direction measured from the (001) plane is 500 or more per square micrometer.