The invention discloses heat treatment method of an aluminum
alloy. The aluminum
alloy comprises, by
mass, 8%-10% of
metal fibers, 5.5%-7.2% of Mg, 1.0%-2.5% of Zn, 0.8%-1.8% of Cu, 0.08%-0.18% of Sc,0.08%-0.18% of Zr, 0.12%-0.22% of Y, 0.02%-0.07% of Si, 0.02%-0.07% of Mn, 0.01%-0.03% of Er, 0.01%-0.03% of Ce, no more than 0.15% of impurities, and the balance Al. The heat treatment method comprises the steps that S1, high-temperature heat treatment is conducted on the aluminum
alloy at the temperature of 500-600 DEG C, and after high-temperature heat treatment,
quenching is conducted on thealuminum alloy with PAG
quenching liquid, so that the aluminum alloy subjected to high-
temperature treatment is obtained, wherein the content of PAG polymers in the PAG
quenching liquid is 15-60 wt%,the temperature of the PAG quenching liquid is 40-80 DEG C, and the stirring speed of the PAG quenching liquid is 100-200 r / s; S2, cold-deformation treatment is conducted on the aluminum alloy subjected to high-
temperature treatment, so that the aluminum alloy subjected to cold deformation is obtained; S3, the aluminum alloy subjected to cold deformation is tempered at the temperature of 300-400 DEG C for 1-2 h; and S4, afterwards, annealing treatment is conducted on the aluminum alloy at the temperature of 100-160 DEG C for 6-8 h, and thus, the strength of the aluminum alloy is improved. Theinvention further provides the aluminum alloy prepared through the heat treatment method.