Evolution of Microstructure and Hardness of 6201 Aluminum Alloy During High-Pressure Torsion Severe Plastic Deformation and Aging

The high-pressure torsion deformation at room temperature of extruded 6201 aluminum alloy with different revolutions (1, 2, 5, 10, 20 r) and the aging treatment at 175℃ for different time intervals (10,60 min) were carried out. The revolution of microstructure and hardness during deformation and aging was studied. The results show that with the increase of high-pressure torsion revolution, the grain size was refined from micrometer to submicrometer, the grains tended to become equiaxed grains, and the hardness of the alloy increased. When the high-pressure torsion revolution was greater than 10 r, the alloy microstructure was stabilized, the grain size was about 183 nm, and the hardness was basically unchanged. With the extension of aging time, the grains of the alloy by high pressure torsion of 10 r gradually grew and were coarsened, and after aging for 60 min, the average grain size of the sub-center position was about 523 nm; the alloy underwent obvious aging softening, and the hardness of the alloy decreased with increasing aging time.