1. Processing strengthened aluminium sheet
Processing hardening is also called cold work hardening, which means that the aluminum sheet is cold deformed below the recrystallization temperature, such as forging, calendering, drawing, drawing, etc. During cold deformation, the dislocation density inside the aluminum sheet increases, and intertwines with each other to form a cellular structure to prevent dislocation movement. The larger the deformation degree, the more severe the dislocation entanglement, the greater the deformation resistance and the higher the strength. The level of hardening after cold deformation varies with the degree of deformation, the temperature of deformation and the nature of the material itself. When the same material is cold deformed at the same temperature, the greater the deformation degree, the higher the strength and the lower the plasticity.
2. Solution strengthened aluminium sheet
Adding some alloying elements to pure aluminium to form infinite solid solution or finite solid solution can not only obtain high strength, but also obtain excellent plasticity and excellent pressure processing function. The most commonly used alloying elements in solution strengthening of aluminium sheets are copper, magnesium, manganese, zinc, silicon and nickel. Usually, the alloying of aluminium sheets constitutes a limited solid solution, such as Al-Cu, Al-Mg, Al-Zn, Al-Si, Al-Mn binary alloys, which constitute a limited solid solution, and all have a larger limit solubility which can play a larger role in solid solution strengthening.
After strengthening, the hardness function of aluminium sheet will be improved remarkably, but its hardness can not always improve; when the upper limit of hardness is reached, no matter what method, the hardness of aluminium sheet can not be improved continuously, only the trademark with higher hardness at the bottom can be chosen.