Influence Of Heat Treatment Process On The Microstructure And Properties Of Deforming Aluminum Alloy Sheet

Deforming aluminum alloy is known to have small density, high strength, corrosion resistance and so on; it has been widely applied in manufacturing industry. But the process of manufacturing is the most overcritical in aluminum manufacturing at present. During the process of manufacturing, heat treatment is closely relative with mechanical properties and forming properties. In this work, the influence of heat treatment on the microstructure,mechanical properties and forming properties process of 5A02,3A21 aluminum alloy sheets.The mechanical properties, electrical properties, microstructure and at different heat treatment condition were investigated using room temperature tensile test, hardness , optical microscopy and electronic microscopy analysis. The results were analyzed and discussed theoretically. Several conclusions can be summaries as follows:(1)With increasing the annealing temperature and elongating the holding time, the tensile strength and the yield strength of 5A02 aluminum alloy sheet decrease slightly, but its elongation and strain hardening exponent increases gradually. The forming properties of the alloy achieve an optimal combination when it is annealed at 380℃for 90min, with the yield ratio is lower and the alloy accomplish the recrystallization and many dimples on the fracture surface.(2)In solution treatment of 3A21 aluminum alloy, the tensile strength and the yield strength increase and then decrease. But, the elongation is opposed. With increasing solution temperature, the micro-hardness decrease. In aging treatment of alloy, the tensile strength and the yield strength decreased and then increase, the elongation increase and then decrease and increase and then increase. The favorable solution-aging treatment of 3A21 alloy is solution at 500℃for 1h, then aging at 200℃for 6h.(3)With increasing the annealing temperature, the earing rate of 5A02 alloy increase and then decreased. At the same annealing temperature, the earing rate decrease with the annealing temperature increase. The earing rate reach the lowest point when annealing temperature and time are 380℃and 90min.(4)At the same solution temperature, the earing rate of 3A21 alloy increase then decrease with aging temperature and aging time increase. The favorable solution-aging treatment of 3A21 alloy is 500℃×1h solution, then aging at 200℃for 6h.