Effect of forging speed on the formability, microstructure and mechanical properties of isothermal precision forged of Al-Zn-Mg-Cu alloy

摘要

An Al-Zn-Mg-Cu support bracket forging was isothermal precision forged at 400 degrees C with speeds of 0.1 mm/s, 0.01 mm/s and transient speed changing from 1 mm/s to 0.01 mm/s by finite element simulation and experiment. The stress concentration at high ribs of the simulated forging corresponded to the defects of under-filling and folding of the experimental forging at the speed of 0.1 mm/s while none defects appeared at the speeds of 0.01 mm/s and transient speed. Besides, not only less time was used to finish forging but also much more fine grains and sub-grains were formed in the forging that precision forged at the transient speed as compared with that at the speed of 0.01 mm/s, which leaded to the higher mechanical properties. Furthermore, the resistance to IGC was much better in the forging that precision forged at the transient speed for the particles eta distributed along the grain boundaries was much wider.