锻造次数对7A04铝合金组织和力学性能影响

采用拉伸试验、冲击试验、硬度检测、金相分析等方法测试和分析了7A04铝合金在不同的锻造次数下的强度、硬度、冲击功和金相组织.结果表明:随着锻造次数的增加,由于晶粒不断细化,强度和硬度逐渐升高,当锻造次数为四次时,晶粒发生了完全动态再结晶,强度和硬度达到最大,继续增加锻造次数强度降低;因为组织中微裂纹的存在,随着晶粒的细化塑性反而减小;冲击功随着锻造次数的增加而减小,三次时达到最小,之后又增大.确定一次和四次为7A04铝合金合适的锻造次数,为该类铝合金零件的锻造工艺的制定提供理论基础.

Effect of Forging Times on Structure and Mechanical Properties of 7A04 Al Alloy

The tensile test, impact test, hardness test and microstructure analysis were used to investigate the mechanical properties and structure of 7A04 alumininm alloy under different forging times. The results show that, with the increase of forging times, because the crystal grain thins unceasingly, the intension and hardness rises gradually, when the forging times is four, the crystal grain has completely dynamic recrystallization, the intensity and hardness are biggest. The forging times increase unceasingly, the intensity reduces. Because the microcrack exists in the organization, the plasticity reduces with the crystal grain thinning. The impact power reduces with the forging times increasing, when the forging times is three, the impact power is biggest, then increases. It is determined that one and four times are appropriate forging times for the 7A04 aluminum alloy. This experiment provides basical theory for forging technology of this aluminium alloy.