Microstructure and Properties of Single-aging 7056 Aluminum Alloy

The hardness, conductivity and microstructure of 7056 aluminum alloys during single-aging treatments at 105, 120, 13, 150 ℃ were investigated by using Vickers, conductivity measurement and transmission electron microscopy (TEM). The results show that the aging response speed of 7056 aluminum alloys was very rapid, the hardness can rose to 188-206 HV for 1 h aging, which was more than 86.9% of the peak-aging hardness. Under the four single-aging temperatures, the major precipitates of this alloy in the peak-aging were all η′ phase. The altering of aging temperature make no remarkable changes of the peak-aging hardness in the alloy, but can significantly accelerate the aging separation process. The microstructure evolution processes of 7056 aluminum alloy during the four single-aging treatments were described as follows: 105 ℃ aging sequence was GPⅠzone +η′(a few)→η′+GPⅠzone (a few)→η′; 120 ℃ aging sequence was GPⅠzone+η′+GPⅡzone (a few)→η′+GPⅡzone (a few)→η′+GPⅡzone (a few); 135 ℃ aging sequence was η′+GPⅡzone→η′+GPⅡzone (a few)→η′; 150 ℃ aging sequence was η′+GPⅡzone (a few) →η′+GPⅡzone (a few)→η+η′(a few).