第二相粒子对铝合金再结晶的影响研究

Influences of Second–Phase Particles on Recrystallization Processes of Al Alloys

对第二相粒子作用下铝合金再结晶过程进行了调研。铝合金显微组织中存在大量的第二相粒子,这些第二相粒子可能来源于凝固过程或者固态相变过程。这些第二相粒子对铝合金的再结晶过程有着巨大的影响。首先,在形核过程中,细小的第二相粒子会阻碍位错的运动,从而使再结晶形核过程减缓;然而,当第二相粒子尺寸较大时,位错会在第二相粒子周围高密度的集中,这会导致再结晶晶核在第二相粒子附近形成。其次,在再结晶晶粒长大过程中,第二相粒子会钉扎晶界的运动,从而减慢再结晶过程。第二相粒子的尺寸、分布对铝合金再结晶形核和长大过程影响的分析是铝合金成分及工艺设计的重要依据。一些先进的加工工艺,比如等径角挤压技术会对第二相粒子的形貌、分布及其与位错和晶界之间的相互作用造成一些特殊的影响。铝合金中第二相粒子对再结晶过程影响因素的分析主要集中在第二相粒子尺寸、分布的分析。第二相粒子形貌及其与基体的界面能对再结晶形核和长大过程也具有重要的影响。

The recrystallization processes of Al alloys under the influences of second–phase particles are investigated.There are many second phase particles in the microstructures of aluminum alloys.These second–phase particles can be formed in the solidification processes or precipitated in the solid phase transformation processes.They have great influences on the recrystallization processes of the Al alloys.Firstly,in the nucleation processes,the fine dispersed second phase particles prevent the dislocation movement,thus slowing down the recrystallization nucleation processes.However,when the sizes of the second–phase particles are large,the dislocations concentrate around the second–phase particles with high density,which leads to nucleation near the second phase particles.Secondly,in the process of recrystallization grain growth,the second–phase particles pin the grain boundary movement,thus slowing down the recrystallization processes.The influences of the size and distribution of second phase particles on the recrystallization processes are very important foundation of the composition and processing technology design of Al alloys.The influence factors of the second–phase particles on the recrystallization processes of Al alloys mainly focus on the analysis of the size and distribution of the second–phase particles.The morphologies of second–phase particles and the particle/matrix interfacial energies also have great influences on the recrystallization processes.