Abstract: Surface mechanical rolling treatment (SMRT) with different loading methods (stress control and strain control) and processing passes was carried out on the annealed 2024 aluminum alloy to study the influence of SMRT on surface roughness and properties. The results show that after SMRT, with the increase of rolling pass, the surface roughness of the specimen first decreases and then increases, a hardness gradient structure is formed inside the specimens, as the distance from the surface increases, the microhardness shows a decreasing trend, and the strength of the specimen is improved, the plasticity decreases slightly, and the fatigue life is significantly enhanced. After stress-control rolled for 5 passes, the comprehensive performance of the 2024 aluminum alloy is the best, with minimum surface roughness of 0.280 μm, hardened layer depth of 600 μm, yield strength of 213 MPa, and tensile strength of 353 MPa. The average fatigue life is twice than that of annealed state, which is increased from 87 000 cycles to 174 000 cycles.

Key words: 2024 aluminum alloy, surface mechanical rolling treatment, surface roughness, tensile properties, hardness, fatigue life