Two-stage aging method for improving intercrystalline corrosion resistance of 6000 series of aluminium alloy

[0021] Example 1

[0022] A two-stage aging treatment method for improving the intergranular corrosion resistance of aluminum alloys. The process steps are: the experimental material is 6061 aluminum alloy, and after solution treatment and water quenching at 530°C/3h, first perform high-temperature pre-aging at 200°C/1h. At this time the hardness is 108HV 0.5 , equivalent to 86% of the peak hardness. Afterwards, low-temperature re-aging at 155°C/120h was carried out to the peak aging state. At this time, the tensile strength and yield strength of the alloy are 351MPa and 326MPa, respectively. The intergranular corrosion sensitivity test shows that the surface of the sample does not have the characteristics of preferential expansion of corrosion cracks along the grain boundaries, but is uniform and smooth, that is, uniform corrosion, such as figure 2 shown.

[0023] Example 2

[0024] A two-stage aging treatment method for improving the intergranular corrosion resistance of aluminum alloys. The process steps are: the experimental material is 6061 aluminum alloy, after solution treatment and water quenching at 560°C/1h, first perform high temperature pre-aging at 180°C/6h, At this time the hardness value is 117HV 0.5 , equivalent to 94% of the peak hardness. Afterwards, low-temperature re-aging at 175°C/16h was carried out to the peak aging state. At this time, the tensile strength and yield strength of the alloy were 362MPa and 332MPa, respectively, and the corrosion behavior was uniform corrosion.

[0025] Example 3

[0026] A two-stage aging treatment method for improving the intergranular corrosion resistance of aluminum alloys. The process steps are: the experimental material is 6061 aluminum alloy, and after solution treatment and water quenching at 540°C/2h, first perform high-temperature pre-aging at 190°C/2h. At this time the hardness is 105HV 0.5 , equivalent to 84% of the peak hardness. Afterwards, low-temperature re-aging at 160°C/72h was carried out to the peak aging state. At this time, the tensile strength and yield strength of the alloy were 353MPa and 328MPa, respectively, and the corrosion behavior was uniform corrosion.