Method for extrusion of aluminum alloy and aluminum alloy material of high strength and high toughness obtained thereby

摘要

An aluminum alloy material of high strength and high toughness and a method for the production thereof are disclosed. The material of high strength and high toughness is produced by laterally changing the direction of extrusion of the aluminum alloy thereby imparting shear deformation productive of such strain intensity equals as an equivalent elongation of not less than 220%, preferably not less than 10,000% to the material in the process of extrusion and reducing the average particle diameter of the grains of a microstructure of the material to minute grains not exceeding 1 micron in diameter. The step of extrusion is carried out at a temperature not exceeding 300° C., preferably not exceeding the recrystallization temperature of the alloy, and more preferably not exceeding the recovery temperature thereof.