退火温度对冷轧态5754铝合金板材组织与性能的影响

Effects of annealing temperature on microstructure and mechanical properties of cold-rolled 5754 aluminum alloy sheet

在160~400℃范围内对5754铝合金冷轧板进行退火处理,通过显微硬度与拉伸性能测试、金相显微组织与拉伸断口形貌观察等,研究5754铝合金冷轧板的再结晶温度以及退火温度对其力学性能和显微组织的影响。结果表明:随退火温度从160℃升高到400℃,板材的伸长率逐渐增加,但硬度、抗拉强度以及屈强比不断降低,屈强比由0.891降低到0.463。退火温度达到360℃后力学性能趋于稳定;冷轧态5754铝板的再结晶温度为294℃,再结晶终了温度为360℃;在290~300℃温度区间内,随退火温度升高,铝板的显微组织变化明显,于290℃退火后基本上呈现原始的纤维状组织,于300℃退火后出现大量的再结晶晶粒。合金冷轧板及其退火后的拉伸断口主要由韧窝和撕裂棱组成,属穿晶型韧性断裂。

The mechanical properties and microstructure of cold-rolled 5754 aluminum alloy sheet annealed from 160 ℃ to 400 ℃ were analyzed using microhardness testing machine, mechanical property testing machine, metallographical microscope and SEM. The effects of annealing temperature on mechanical properties, and microstructures of the fractrure surface were discussed. The results show that the elongation of A1 alloy sheet increases gradually with increasing annealing temperature from 160 ℃ to 400 ℃, but the hardness, tensile strength and yield ratio decrease constantly. Especially, the yield ratio decreases from 0.891 to 0.463. The mechanical properties tend to be stable after annealing temperature reaching 360 ℃. The recrystallization temperature of cold-rolled 5754 aluminum alloy sheet is 294 ℃, and the end recrystallization temperature is 360 ℃. The microstructure changes significantly with the increase of annealing temperature from 290 ℃ to 300 ℃. The microstructure of Al alloy sheet annealed at 290 ℃ basically presents the original fibrous microstructure, while the microstructure of Al alloy sheet annealed at 300 ℃ ethicist a lot of recrystallized grains. Tensile fracture is mainly composed of ductile dimples and tearing edges, which presents intergranular ductile fracture. Key words： 5754 aluminum alloy; cold rolling; annealing temperature; recrystallization temperature; fracture surface