均匀化退火对低Fe/Si 比Al-Mn合金微观组织演变的影响

Evolution of microstructure in low Fe/Si Al-Mn alloy during homogenization

摘要:

本文主要研究了双辊轧制的低Fe/Si 比Al-Mn合金在不同均匀化处理过程中的微观组织演变情况。当对合金进行550℃/4h的均匀化处理时,合金表面的晶粒组织从典型的纤维组织转变成粗大的长条状再结晶晶粒组织。合金心部的晶粒组织则随着均匀化温度的升高而趋向于等轴化。当对合金进行450℃/4h和500℃/4h的均匀化处理时,粗大的初生相开始破碎,当均匀化温度升高至550℃时,破碎的初生相发生粗化。在450℃/4h和500℃/4h的均匀化处理条件下,弥散相在均匀化过程中的演变主要受形核和长大机制控制,而在550℃/4h的均匀化条件下,弥散相的粗化和回溶成为主要机制。当对合金进行500℃/4h处理时,大量细小的含Zr弥散相从过饱和固溶体中析出。

Abstract:

The evolution of microstructure in Al-Mn alloy with a low ratio of Fe/Si produced by twin-roll casting (TRC) during various homogenization treatments has been investigated. The grain structure near the surface transforms from fibrous to coarse elongated recrystallized grain structure during homogenization at 550℃ for 4h. The grain in the interior tends to be equiaxed with the temperature. The primary particles are broken up after homogenization at 450℃ and 500℃ for 4h, respectively, and coarsened when temperature increases to 550℃. The evolution of dispersoids is controlled by nucleation and growth mechanisms at 450℃ and 500℃ for 4h, respectively, whereas the coarsening and dissolution are predominant mechanisms during homogenization at 550℃ for 4h. Many small size Zr-bearing dispersoids are obtained during homogenization at 500℃ for 4h.