关键词: 铝合金, 均匀化退火, 第二相, 晶粒, 硬度

Abstract: Effect of different homogenization annealing temperatures and time on microstructure and hardness of as-cast 1085 alloy was studied by means of JMatPro thermodynamic calculation software, differential scanning calorimeter, microstructure observation, energy spectrum analysis and hardness test. The results show that the continuous strip-like Al₃Fe phase is distributed at the grain boundary of the original as-cast alloy, and there are quasi-circular Al₃Fe and Al₈Fe₂Si eutectic phases in the grains. After homogenization annealing, the Fe-containing phase at grain boundary gradually changes into discontinuous distribution, the amount of Fe-containing phase in the grains decreases, and the area fraction of Fe-containing phase decreases continuously with the increase of homogenization annealing temperature and time, and tends to be stable after the temperature and time reach 520 ℃ and 8 h. The average grain size increases slowly with the increase of homogenization annealing temperature and time, and the hardness increases slowly with the increase of homogenization annealing temperature, which tends to be stable after the temperature and time reach 520 ℃ and 8 h. Based on the evolution of Fe-containing phase, grain growth behavior and hardness change law, the optimal homogenization annealing process is 520 ℃ for 8 h.

Key words: aluminum alloy, homogenization annealing, second phase, grain, hardness